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Raympnd  Pettibon 


* 


THE  ASSAYEB’S  GUIDE. 


Digitized  by  the  Internet  Archive 
in  2016 


https://archive.org/details/assayersguideorpOOIieb 


THE 


ASSAYER’S  GUIDE; 

OR, 

PRACTICAL  DIRECTIONS  TO  ASSAYERS, 
MINERS,  AND'  SMELTERS, 

FOR  THE 

TESTS  AND  ASSAYS.  BY  HEAT  AND  BY  WET  PROCESSES. 

OF  THE 

ORES  OF  ALL  THE  PRINCIPAL  METALS, 

OF 

GOLD  AND  SILVER  COINS  AND  ALLOYS, 
AND  OF  COAL  &c. 


BY 

OSCAR  M.  LIEBER, 

LATE  GEOLOGIST  TO  THE  STATE  OF  MISSISSIPPI. 


PHILADELPHIA  : 

HENRY  CAREY  BAIRD  & CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTERS, 

810  Walnut  Street. 

1880. 


Entered  according  to  Act  of  Congress,  in  tl  e year  1852,  by 
HENRY  CAREY  BAIRD, 

the  Clerk’s  Office  of  the  District  Court  of  the  United  States  in  and  for  the 
Eastern  District  of  Pennsylvania. 


PREFACE. 


iv  i/r  * tenting  this  little  volume  to  the 
^ablio^  I xrust  that  I am  filling  a void  in  our 
chemical  literature.  I believe  there  is  no 
work  in  the  English  language  on  assaying 
which  combines  with  practical  usefulness  a 
sufficiently  popular  character  for  those  read- 
ers who  have  not  made  metallurgy,  and  its 
kindred  sciences,  objects  of  their  especial 
study.  My  desire  is,  to  offer  a book  which 
fully  treats  of  all  the  subjects  of  assay- 
ing, and  whose  price  will  yet  place  it 
within  the  reach  of  all  persons  profession- 
ally interested  in  this  important  branch  of 
knowledge. 

The  more  compendious  works  on  chemis- 
try, if  they  allude  to  assaying  at  all,  give  so 
sparing  and  incidental  remarks,  that  they 
do  not  throw  any  light  upon  it  for  technical 

1*  5 


6 


PREFACE. 


purposes,  as  indeed  it  does  not  fall  within 
their  province  to  do. 

The  immense  mineral  wealth  of  the 
United  States,  to  which  the  discoveries  in 
California  have  so  largely  added,  makes  this 
art  a very  desirable  acquirement  for  every 
one  engaged  in  any  business  connected  with 
the  metals;  and  it  would  appear  indispensa- 
ble to  those  desirous  of  deriving  the  great- 
est advantage  from  a residence  in  that 
promising  and  alluring  part  of  our  country. 

Although  these  pages  principally  treat  of 
the  processes  by  heat,  I have  thought  it 
proper  to  describe  also  some  wet  processes, 
either  where  they  serve  as  methods  to 
rectify  the  former,  or  where  no  others  exist; 
as,  for  instance,  is  the  case  with  platinum. 
For  the  coins,  I have  selected  those  em- 
ployed at  mints,  and  which  are  therefore 
generally  considered  the  most  serviceable 
for  the  analysis  of  those  alloys. 

I feel  induced  here  to  recommend  at  least 
a partial  study  of  blowpipe  assaying,  to 
those  who  may  wish  to  make  use  of  the 


PREFACE. 


T 


instructions  given  in  this  treatise.  This 
infant  branch  of  chemistry  was  first  created, 
I may  say,  in  Sweden  by  Cromsted,  and 
established  more  firmly  by  Gahn  and  Ber- 
zelius, both  his  countrymen;  and  has  of  late 
been  made  by  Plattner  a method  even  for 
quantitatively  ascertaining  the  contents  of 
most  minerals. 

The  requisite  blowpipe  utensils  for  the 
mere  detection  of  the  principal  components 
of  ores  are  so  few,  can  so  easily  be  com- 
manded, and  may  be  so  readily  carried  about 
one’s  person,  that,  at  least  for  the  purpose  of 
a prior  test,  it  is  very  advisable  to  possess 
some  knowledge  of  their  application,  which 
can  be  acquired  with  great  facility. 

I beg  to  refer  those  readers  who  may 
be  desirous  of  pursuing  assaying  more  sci- 
entifically, in  particular  to  two  works  of 
merit,  neither  of  which  is  written  in  our 
language.  The  one  is  the  Trait6  des  Essais 
par  la  Yoie  seche,  by  Berthier,  Paris,  1834; 
the  other  is  in  German, — Instructions  on 
Assaying,  for  Miners  and  Smelters,  by 


8 


PREFACE. 


Bodeman,  Clausthal,  1845.  The  last  men- 
tioned work  has  been  of  much  use  to  me  in 
writing  this  volume. 

I cannot  conclude  these  brief  remarks 
without  seizing  upon  the  opportunity  of 
acknowledging  the  liberality  of  a distin- 
guished officer  at  Freiberg  in  Saxony,  Mr, 
F r itz  s ch  e,  ch  ief  a s say  er  of  that  mining  district. 
I have  made  frequent  use  of  his  notes  and 
hints,  given  me  while  I had  the  advantage 
of  a personal  intercourse  with  him. 

0.  M.  L. 


Columbia,  S.  C.,  10 th  April , 1851. 


CONTENTS. 


PASS, 

Preface . 5 

Explanation  of  Technical  and  Scientific  Terms.. . 11 

Introduction . 13 

I.  Description  of  Implements  and  Utensils 

used 17 

II.  Assay  of  Silver  Ores  by  Heat — Cupellation  39 
[II.  A Table  to  rectify  the  Loss  in  the  Silver 

Assay 52 

IY.  Gay-Lussac’s  Process  for  Silver  Alloys 54 

Y.  Assay  y>f  Gold  Ores  by  Heat — Quartation  . 56 

VI.  by  Amalgamation 61 

YII.  by  Washing 63 

VIII.  by  a Wet  Process 66 

IX.  Assay  of  Silver  Coins,  or  Alloys  of  Silver 

and  Copper 68 

X.  Assay  of  Gold  Coins,  or  Alloys  of  Gold, 

Silver,  and  Copper 71 

XI.  To  find  the  Proportion  of  Gold  in  a Mixture 

of  Gold  and  Quartz,  by  Calculation...  77 

XII.  Assay  of  Platinum  Ores 80 


9 


10 


CONTENTS. 


XIII.  Assay  of  Copper  Ores  by  the  German  or 

Hungarian  Method 

XIY.  Assay  of  Copper  Ores  by  the  English 

Method 

XY.  Assay  of  Lead  Ores  by  Heat  

XYI. by  a Wet  Process.... 

XYII.  Assay  of  Iron  Ores  by  Heat 

XYIIL  Fuchs’s  Process  for  Iron  Ores  and  Iron. . . 

XIX.  Assay  of  Ores  of  Mercury 

XX.  Assay  of  Sulphurets  in  Ores 

XXI.  Mode  of  Testing  the  Calorific  Power  of 

Coal  and  other  Fuels.. 

XXII.  Tables 125- 


85 

92 

97 

100 

103 

108 

111 

119* 

121 

•129 


EXPLANATION 


OF 

TECHNICAL  AND  SCIENTIFIC  TEEMS  USED. 


Alkaline,  containing  an  alkali,  viz.  potash,  soda,  or  am- 
monia. 

Ammoniacal,  containing  ammonia  or  hartshorn. 

^Assays  by  Heat,  or  processes  by  the  sole  means  of  fire. 

Black  flux.  See  Copper  Assays. 

Carats  fine , a term  used  in  designating  the  value  of  gold 
alloys. 

Carbonate,  applied  to  oxides,  where  carbonic  acid  is 
united  with  them. 

Chlorides  are  combinations  of  chlorine  with  metals,  &c. 

Crucible.  See  Utensils,  &c. 

Cupel.  See  Utensils,  &c. 

Fluxes , ingredients  added  to  produce  slags. 

Fuming  nitric  acid,  the  strongest  kind,  emitting  red 
vapours. 

Galena,  a lead  ore. 

Hygroscopic  water,  the  moisture  bodies  attract  from  the 
atmosphere. 

Muffle.  See  Utensils,  &c. 


11 


12  EXPLANATION  OF  TECHNICAL  TERMS. 


Oil-baths,  heated  oil,  to  warm  solutions,  &c. 

Oxidation,  the  combining  with  oxygen  (rusting,  &c.) 

Peroxide,  the  oxide  containing  the  greatest  amount  of 
oxygen. 

Phosphates,  combinations  of  phosphoric  acid  with  metals, 
earths,  (earthy,)  &c. 

Precipitation,  the  production  of  insoluble  compositions, 
&c.  in  wet  processes. 

Protoxide , containing  the  least  amount  of  oxygen. 

Quartation.  See  Gold  Assays. 

Sand-bath,  heated  sand,  to  warm  solutions,  &c. 

Sulphates,  combined  with  sulphuric  acid. 

Sulphurets,  combined  with  sulphur. 

Test-glass,  a glass  tube  closed  at  one  end  for  chemical 
purposes. 

Water-bath,  heated  water  to  warm  solutions  at  212° 
Fahrenheit. 

Water  of  crystallization,  the  water  contained  in  crystals, 
and  by  evaporating  which,  they  crumble. 

Wet  'processes  are  those  in  which  acids  and  solutions  are 
used,  and  where  fire  is  never  directly  employed. 

White  flux.  See  Copper  Assay. 


THE 


AS  SAYERS  GUIDE. 


INTRODUCTION. 

Assaying  is  the  science  whic'h  treats  of  the 
various  methods  of  ascertaining  the  amount 
of  one  or  of  several  ingredients  of  a chemical 
compound,  such  as  an  ore  or  alloy,  but  is 
solely  intended  for  practical  purposes.  For 
this  reason  one  of  its  main  objects  is  to  be 
able  to  attain  to  a very  great  accuracy  with 
the  smallest  and  cheapest  means,  and  in 
the  shortest  possible  time.  In  this  it  is  con- 
tradistinguished from  inorganic  analytical 
chemistry,  properly  so  called.  The  aim  of 
the  latter  is  to  ascertain  all  the  different 
composing  elements  of  an  inorganic  com- 
pound, and  also  the  exact  amount  of  each. 

2 13 


14 


THE  ASSAYER’S  GUIDE. 


and  for  this  reason  the  chemist  should  never 
be  deterred  by  a great  waste  of  time  and 
money,  if  an  accurate  result  should  require 
extravagant  means.  As  assaying  is  only  an 
aid  to  technical  operations,  and  these  never 
can  extract  the  whole  amount  of  a metal  or 
other  component  part  contained  in  a com- 
position, (be  the  latter  a natural  or  artificial 
one,)  with  true  chemical  precision,  it  is  self- 
evident  that  much  time  and  labour  would 
be  unnecessarily  lost,  if  the  same  attention 
were  devoted  to  it  as  would  be  requisite 
in  an  analysis.  This,  however,  also  shows 
that  it  is  utterly  inadequate  for  purely 
scientific  ends. 

Assaying  was  the  earliest  known  branch 
of  chemistry,  and  in  fact  that  one  which 
afterward,  through  the  medium  of  the 
various  investigations  of  alchemy,  drew 
attention  to  theoretical  chemistry,  and  thus 
founded  that  science. 

The  art  of  assaying  is  so  ancient,  and  it 
has  so  constantly  and  imperceptibly  re- 


INTRODUCTION. 


15 


ceived  new  additions  and  perfections,  that 
its  origin  is  entirely  unknown.  Agricola 
of  Saxony,  who  lived  in  the  earliest  half  of 
the  sixteenth  century,  was  the  first  to  col- 
lect the  facts  and  \^rite  on  this  subject, 
(G.  Agricola  de  Re  Metallica,  libr.  XII. 
Basil,  1546.)  Since  then  the  manifold  dis- 
coveries of  more  enlightened  periods  have 
vastly  enlarged  and  developed  this  branch 
of  study. 

It  is  not  by  any  means  always  necessary 
that  the  same  measures  be  employed  for 
these  tests  as  are  used  in  the  separation  of 
the  single  constituent  from  the  rest  of  the 
compound  in  large  quantities;  as,  for  in- 
stance, in  the  processes  of  smelting  and 
amalgamation,  although,  if  convenient,  it  is 
very  advisable,  as  it  facilitates  the  metal- 
lurgist in  the  detection  of  the  best  fluxes 
and  admixtures  to  be  added  to  his  peculiar 
ores. 

The  assayer  should  be  guided  in  his 
operations  by  chemistry,  and  the  study  of 


16 


THE  ASSAYER'S  GUIDE. 


the  latter,  particularly  as  far  as  regards  the 
principal  and  more  common  substances, 
should  never  be  omitted.  In  other  respects, 
all  that  can  be  recommended  to  one  who 
desires  to  perfect  himself  in  assaying,  is  the 
most  scrupulous  cleanliness,  order,  and  pre- 
cision as  regards  his  assays  and  implements, 
and  the  most  unwearying  adroitness  and 
attention  in  performing  the  manipulations 
required  by  his  science. 


17 


I. 

Description  of  the  Implements  and  Utensils 
used  in  the  course  of  Assays  by  Heat. 

Among  the  articles  necessary  for  an 
assayer’s  office,  of  course  the  first  that 
requires  a description  is  the  furnace.  For 
most  purposes  the  muffle  furnace  suffices, 
and  it  is  the  only  one  used  for  gold,  silver, 
and  copper  ores ; but  for  iron,  lead,  &c.  we 
require  another,  though  much  simpler  one. 
I shall  first  describe  the  muffle  furnace, 
(Plate  I.  figs.  1,  2,  and  3.)  The  character- 
istic part,  the  one  from  which  this  furnace 
derives  its  name,  is  the  muffle,  illustrated 
on  the  same  plate,  in  figs.  7 and  8.  Both 
these  diagrams  give  a perspective  view,  the 
first  a semilateral,  the  second  one  from  m 
front.  They  can  be  procured  in  most  of 
our  larger  cities,  and  are  manufactured  in 

3* 


18 


THE  ASSAY  ER’S  GUIDE. 


great  quantity  in  Hessia,  of  a very  firm  and 
fire-proof  siliceous  clay,  the  same  material 
as  that  used  for  the  well-known  Hessian 
crucibles,  (Plate  II.  fig  5.)  The  one  from 
which  the  drawing  was  taken  in  Plate  I. 
measures  eight  inches  across  the  bottom 
from  mouth  to  back  outside,  arid  four 
inches  down  the  back.  The  holes  opening 
upwards  towards  the  interior  measure  each 
an  inch  and  a half  lengthways,  but  their 
number  of  course  varies  according  to  the 
size  of  the  muffle,  which  again  should 
depend  on  the  quantity  of  assays  expected 
to  be  performed  at  once.  The  back  and 
the  mouth  of  the  muffle  are.  equal  in  size. 

The  muffle  furnace  is  exhibited  from  in 
front  in  fig.  1,  in  a lateral  section  in  fig.  3, 
and  in  a transverse  perpendicular  section  in 
fig.  2.  A scale,  showing  the  proportionate 
dimensions  in  English  feet,  is  attached,  to 
facilitate  the  use  of  the  drawings  in  build- 
ing a furnace ; for  though  very  small,  they 
have  been  made  with  much  care,  and,  with 


DESCRIPTION  OF  IMPLEMENTS. 


19 


the  little  sketches  attached,  are  fully  capa- 
ble of  being  employed  to  that  effect.  As 
will  be  seen  from  the  first  figure,  the  line 
A B is  seven  feet  long,  while  the  external 
width  of  the  furnace,' C D,  is  two  feet  nine 
inches.  The  furnace  consists  of  three  chief 
parts,  the  chimney,  r,  in  figs.  2 and  3,  (which 
need  only  be  3i  feet  high  if  it  enters  the 
chief  chimney  of  the  laboratory,  which 
should  then  measure  at  least  9 — 12  feet,) 
the  part  above  C D,  in  fig.  1,  containing  the 
muffle,  and  the  part  below  that,  the  grate, 
ashes  box,  &c.  &c.  In  fig.  1 we  see  imme- 
diately below  the  chimney  a representation 
of  bricks,  { firebricks , for  all  in  immediate 
contact  with  the  heat  should  be  of  this 
kind ; the  external  ones  are  common  burnt 
bricks.)  These,  though  fastened  in  tight, 
are  placed  so  that  they  can  be  taken  out, 
to  put  in  a new  muffle,  or  make  other 
repairs  when  necessary.  In  this  brickwork 
we  have  two  openings,  d and  a.  The 
former  is  only  a small  aperture,  for  insert- 


20 


THE  ASSAYER’S  GUIDE. 


ing  pieces  of  sheet  iron,  upon  which  to  dry 
the  cupels.  It  is,  however,  not  immediately 
necessary,  and,  if  present,  is  always  closed 
with  a tight  brick  when  the  muffle  is  in  use. 
a is  the  opening  of  the  muffle,  which  can  be 
closed  by  a piece  of  fire-proof  brick  repre- 
sented in  fig.  4,  having  an  iron  piece  pro- 
truding on  the  exterior,  with  a narrow 
opening,  into  which  fits  the  handle  fig.  5, 
which  we  apply  on  removing  it.  To  the 
right  and  a little  below  the  muffle  is  a 
loose  brick,  e,  to  be  taken  out  whenever  it 
becomes  necessary  to  remove  the  fire-proof 
clay  bar,  o,  which  holds  the  muffle,  (vid.  fig. 
2.)  As  seen  in  fig.  3,  this  bar  as  well  as 
the  three  others  shown  in  the  little  sketch 
affixed  to  fig.  2,  and  of  which  the  centre 
one  is  a little  the  longest,  are  slightly 
inclined,  thus  elevating  the  back  of  the 
muffle  an  inch  above  the  front,  and  giving  a 
better  circulation  of  heat,  as  should  be  the 
case  where  stone-coal  or  cokes  are  used. 
In  burning  charcoal  it  may  be  horizontal, 


DESCRIPTION  OF  IMPLEMENTS. 


21 


although  this  inclination  has  another  ad- 
vantage, inasmuch  as  it  enables  us  to 
clean  out  the  muffle  easier,  should  a cupel 
upset,  the  contents  running  forward.  The 
three  fireclay  bars,  s s's,  are  loose,  while  o is 
inlaid  on  one  side,  and  on  the  other  fastened 
in  with  a loose  piece  of  brick  and  an  iron 
wedge,  which  can  be  removed,  as  already 
remarked,  through  e.  On  inserting  the  bars 
and  muffle,  the  parts  where  they  meet,  and 
where  the  former  touch  the  other  bricks, 
should  be  powdered  over  with  bone-ashes,  to 
prevent  a possible  adhesion  from  the  intense 
heat.  Small  cracks  in  the  muffle  should 
be  mended  with  coarsely  powdered  burnt 
clay,  p,  in  fig.  2,  is  the  open  space  left  round 
the  muffle  about  an  inch  and  a half  wide, 
and  into  which  the  opening  d in  figs.  1 and 
3 leads.  Immediately  below  C D we  have 
the  door  b exhibited  in  all  three  figures. 
It  is  for  the  introduction  of  fuel,  and  is  just 
above  the  grate,  x x,  in  figs.  2 and  3,  which 
consists  of  six  iron  bars  placed  in  the  same 


22 


THE  ASSAYER’S  GUIDE. 


inclination  as  the  muffle.  The  door  /,  fig,  1, 
is  of  iron,  with  an  inside  coating  of  fire-clay, 
an  inch  and  a quarter  thick,  kept  in  place  by 
iron  rivets,  thus  protecting  the  assayer  from 
the  radiating  heat  of  the  iron,  which  would 
otherwise  soon  be  white-hot.  Below  the 
grate  stretches  the  chamber  q , in  figs.  2 and 
3,  both  for  draught  and  for  the  cinders. 
The  plane  at  the  bottom  of  this  is  inclined 
like  the  grate  and  muffle,  and  has  the 
opening  c to  take  out  the  ashes.  To  intro- 
duce a regular  and  sufficient  quantity  of 
atmospheric  air,  the  channel  k has  to  be 
constructed,  which  enters  q at  A,  and  passing 
under  the  floor  of  the  laboratory  opens 
outside  at  i,  fig.  3 : l is  a small  piece  of 
sheet  iron,  by  pulling  out  or  pushing  in 
which,  we  open  or  close  the  passage  h at 
pleasure,  and  accordingly  as  we  require  a 
great  influx  of  air  or  not,  for  a high  or  low 
temperature.  The  little  figure  annexed  to 
fig.  1,  shows  the  construction  of  the  little 
opening  and  slide  in  the  lower  door.  It  is 


DESCRIPTION  OF  IMPLEMENTS.  2b 

exactly  as  with  a common  iron  stove,  y 
being  the  hole,  while  the  slide  a (3  can  be 
closed  over  it  by  means  of  the  handle,  or 
removed,  as  may  be  desirable  for  different 
degrees  of  ventilation.  This  furnace  is  of 
the  kind  proposed  by  Professor  Plattner  for 
the  Freiberg  assay  office  for  the  use  of  stone- 
coal  and  cokes,  and  where  it  has  been 
employed  to  great  advantage,  as  regards 
economy  and  practicability  in  general. 

Having  thus  pretty  minutely  given  a 
description  of  the  muffle  furnace,  as  it  can 
best  be  constructed  when  not  required  to  be 
movable,  I shall  proceed  to  the  furnace  for 
tests  of  iron  ores,  lead  ores,  &c.,  also  in  a 
shape  not  intended  to  be  moved,  as  repre- 
sented by  a lateral  section  in  fig,  6,  Plate  I. 
Those  parts  in  immediate  contact  with  the 
heat  should  be  constructed  of  fire-proof 
bricks,  which  ought  to  reach  some  distance 
up  the  chimney.  The  main  body  of  the 
furnace  B and  A is  either  square  or  round, 
and  twelve  inches  in  diameter.  The  back 


24 


THE  ASSAYER  S GUIDE. 


is  about  three  feet  nine  inches  high,  while 
the  front  measures  slightly  less,  as  the  top 
has  a little  slant,  merely  for  convenience  in 
easier  being  able  to  get  at  the  bottom.  A 
is  the  part  where  the  ashes  collect,  with  a 
door  at  H having  one  or  several  openings, 
as  is  represented  in  the  door  <7,  in  fig.  1,  for 
the  sake  of  regulating  the  ventilation.  If 
this  furnace  is  to  be  used  for  iron  assays, 
in  which  case  a very  intense  heat  is  requk 
site,  a similar  channel  as  illustrated  in  K, 
fig.  3,  should  be  attached,  the  longer  the 
better,  and,  if  possible,  opening  into  some 
cool  place,  e.  g.  a cellar,  thus  creating  a 
stronger  current  of  air,  and  consequently  a 
better  ventilation.  Above  A are  the  bars 
forming  the  grate  F G,  which  ought  to  vary 
in  distance  from  one  another  according  as 
we  use  charcoal  or  stone-coal  and  cokes,  in 
the  former  case  being  closer  to  one  another* 
B is  the  part  in  which  the  crucibles  are 
placed,  as  well  as  the  fuel,  and  which  has 
one  opening  for  the  introduction  of  the  same 


DESCRIPTION  OF  IMPLEMENTS.  25 

with  the  cover  E,  suspended,  when  open, 
by  a chain,  but  which  is  shut  when  the 
furnace  is  in  use.  This  cover  is  commonly 
of  iron,  covered  with  fireproof  clay. 

C is  the  channel  leading  off  to  the 
chimney  D,  which  may  vary  in  width  from 
one  half  to  one  quarter  the  width  of  B. 
For  assays  of  lead  and  copper  it  is  not 
necessary  to  have  the  chimney  very  high, 
as  no  very  severe  draught  is  required ; but 
for  iron  assays  it  should  be  about  thirty  feet. 
Iti  the  assay  office  in  Clausthal  it  measures 
forty-eight  feet.  In  this  case,  of  course,  if 
there  is  also  a muffle  furnace  on  the  same 
hearth,  it  is  best  to  conduct  the  chimneys 
of  both  into  one  large  one.  On  placing 
the  crucibles  in  this  furnace- — twelve  have 
room  in  it  at  once — a piece  of  firebrick,  K 
in  the  drawing,  is  first  placed  on  the  grate, 
which,  to  avoid  adhesion  of  the  crucibles, 
may  be  powdered  with  bone-ashes.  This 
brick  is  employed  to  have  the  crucibles 
more  in  the  focus  of  heat,  by  elevating 

3 


26 


THE  ASSAYEE’S  GUIDE. 


them  above  the  coal  around  it,  and  also — 
clay  being  a bad  conductor — to  keep  them 
from  immediate  contact  with  the  cold  blast. 
The  fuel  should  never  be  heaped  above  I, 
the  mouth  of  the  channel  C,  and  large  coals 
should  be  placed  below,  to  keep  the  grate 
from  choking.  If  several  crucibles  are  used 
at  once,  they  ought  to  stand  sufficiently 
apart  to  admit  coals  between  them,  as  they 
otherwise  might  melt  partially  in  the  course 
of  the  process,  and  form  one  compact  mass. 

On  the  foregoing  pages  I have  furnished 
descriptions  and  measurements  of  furnaces, 
which,  as  I have  already  remarked,  though 
easily  constructed,  are  not  portable;  and  it 
is  proper  that,  before  closing  this  chapter,  I 
should  devote  a few  lines  to  the  mention  of 
those,  which,  from  their  being  movable,  and 
thus  obviating  the  difficulty  and  incon- 
venience of  constructing  one,  might,  in 
many  cases,  be  preferred,  although  their 
smaller  dimensions,  as  a matter  of  course, 
make  it  more  difficult  to  perform  good 


DESCRIPTION  OF  IMPLEMENTS. 


27 


assays,  and  impossible  to  attend  to  many  at 
a time.  Among  these  we  have  both  muffle 
furnaces,  and  wind  furnaces  such  as  last 
described.  They  are  made  of  sheet  iron, 
strongly  fastened  wdth  iron  hoops  and 
coated  inside  with  fireclay,  (see  also  Chap. 
XVI.)  They  can  generally  be  procured  at 
all  larger  stores  of  chemical  apparatus. 
Luhme  & Co.  of  Berlin,  who  have  one  of 
the  largest  assortments  of  such  articles  in 
Europe,  and  for  comparatively  cheap  prices, 
furnish  a kind  which  may  be  used  for  both 
purposes,  for  50  Prussian  dollars,  about 
$35.00  our  money.  There  is  another  kind 
of  portable  furnace  with  an  iron  muffle,  but 
which  can  only  be  applied  to  silver  and 
gold  assays,  (coin,)  which  may  suffice  for 
the  wants  of  many,  and  which  is  more 
durable  than  the  others.  After  having 
thus  given  a description  of  the  furnaces 
used  in  the  course  of  the  experiments 
elucidated  in  the  following  pages,  I shall 
venture  to  call  the  reader’s  attention  to 


28 


THE  ASSAYER’S  GUIDE. 


other  instruments  used  in  the  assays  of  ores. 
Among  these,  probably,  the  balance  will 
appear  most  conspicuous.  There  ought  to 
be  two  in  use,  one  very  accurate,  the  other 
less  so,  for  more  common  purposes,  as 
weighing  off  the  ingredients  or  admixtures, 
such  as  pure  lead,  borax,  &c.  The  other 
one  should  be  made  with  great  care,  and 
only  used  to  weigh  off  the  small  buttons  of 
gold  and  silver  procured.  Accurate  ana- 
lytical scales  are  required;  and  should  it 
be  more  practicable  to  possess  them  in  a 
small  and  compact  shape,  I would  propose 
the  blowpipe  balance  suggested  by  Professor 
Plattner  of  Freiberg,  and  made  in  that 
place  by  a very  careful  workman  of  such 
instruments,  Mr.  Beschorner,  who  furnishes 
them  for  all  the  students  of  the  mining 
academy  there.  This  balance  can  be  pro- 
cured most  simply  from  Luhme  & Co.  in 
Berlin,*  who  are  in  constant  connection 


* J.  F.  Luhme  & Co.,  51  Kurstrasse,  Berlin. 


DESCRIPTION  OF  IMPLEMENTS. 


29 


with  the  United  States,  and  furnish  them 
handsomely  got  up,  with  an  elegant  ma« 
hogany  box,  containing  weights  of  platinum 
down  to  one-tenth  of  a milligramme,  01 
0.003543402  grs.  Troy,  for  about  $16. 
The  same  firm  can  also  provide  common 
balances,  from  Professor  Wackenrode’s  (of 
Jena)  description,  for  $4  or  $5.  It  would 
be  very  advisable  to  have  a medium  balance 
to  employ  with  the  baser  metals,  marking 
a milligramme  with  about  twenty-five 
grammes  weight,  costing  about  $13  or  $14. 
It  will  be  unnecessary  to  give  a drawing  of 
these  balances,  and  I believe  the  short  de- 
scription is-  sufficient  to  define  the  accuracy 
and  qualities  required.  I may  add,  how- 
ever, that  it  is  highly  advisable  to  have 
wires  of  platinum  used  everywhere  in  the 
more  exact  ones,  since  then  an  unequal 
extension  or  contraction  of  the  silk  cords, 
otherwise  commonly  used,  and  which  neces- 
sarily cause  variations,  is  avoided. 

We  must  now  cast  a glance  at  th« 

3* 


30 


THE  ASSAYER’S  GUIDE. 


smaller  and  less  costly  utensils,  but  all 
of  which  are  necessary  for  the  accomplish- 
ment of  the  operations  to  be  performed  as 
directed  in  the  following  pages.  I allude 
to  the  crucibles,  cupels  or  cups,  and  tongs, 
&c.,  illustrated  in  Plate  II.  The  former, 
figs.  1,  2,  3,  4 and  5,  are  all  of  their  natu- 
ral size  in  the  drawings.  Figs.  1,  3,  and  4, 
should  be  made  from  accurate  descriptions 
by  a potter,  of  a pure  clay,  containing  as 
little  silica  mechanically  combined  as  pos- 
sible, since  its  presence  prevents  the  ves- 
sels from  being  sufficiently  porous  to  allow 
the  oxidizing  metals  to  enter,  which  would, 
as  will  hereafter  be  seen,  become  a great 
drawback  to  the  assay.  Some  hundreds 
must  always  be  kept  on  hand,  for  they  can 
only  be  used  once,  as  the  lead,  almost  al- 
ways present,  glazes  them  immediately. 

Fig.  1 represents  a cupel  used  in  the 
operation  technically  termed  cupellation  of 
the  gold  and  silver  ores : a shows  it  from 
above,  b from  the  side.  The  concave  inner 


DESCRIPTION  OF  IMPLEMENTS. 


31 


surface  should  not  be  too  shallow,  thus 
letting  the  contents  run  over ; nor,  on  the 
other  hand,  too  deep,  in  which  case  too 
small  a surface  would  be  exposed  to  the 
oxidizing  power  of  the  heat.  The  line 
given  in  b shows  the  proper  inclination 
within. 

Fig.  2 is  a truncated  cone,  with  a very 
slightly  concave  surface  at  the  wider  ex- 
tremity or  top.  It  is  made  in  great  part  of 
bone-ashes,  being  among  the  most  porous 
substances  that  can  stand  a high  tempera- 
ture. I give  here  a recipe  for  their  pre- 
paration, furnished  me  by  Mr.  Fritzsche. 
It  shows  the  relative  quantity  of  the  ingre- 
dients as  used  for  these  cupels  at  his  office, 
where  they  are  made  by  the  laboratory 
servant  in  wooden  moulds,  using  a rod, 
shaped  like  a pestle,  to  make  the  hollow 
at  the  top.  The  mass  consists  of  4 parts 
of  wood-ashes  previously  freed  of  the  pot- 
ash by  filtration,  I part  of  lime,  and  1 part 
of  bone-ash. 


32 


THE  ASSAYER'S  GUIDE. 


Fig.  3 shows  a flat,  shallow  crucible/ 
made  of  the  same  pure  clay  as  that  repre- 
sented in  fig.  1 : a is  the  cup  as  seen  from 
above,  while  b gives  a lateral  view,  show- 
ing also  the  curve  of  the  inner  surface. 
This  vessel  is  used  in  the  assay  of  copper, 
as  well  as  fig.  4.  Fig.  3 is  termed  in  Ger- 
man u Kupfer  Garscherbe ,”  from  the  fact 
that  with  its  use  the  copper  assay  is 
finished. 

Fig.  4 is  a high  crucible,  as  mentioned 
above,  used  for  copper  and  lead.  It  is 
made  of  the  same  material  as  the  former. 
The  reason  of  its  having  so  great  a height 
compared  with  its  width,  and  otherwise  so 
peculiar  a form,  is  to  concentrate  all  the 
heat  round  about  the  bottom  of  the  in- 
terior. In  some  places,  in  lieu  of  better, 
the  Hessian  crucible  (fig.  5)  is  used;  but 
No.  4 is  much  better  adapted,  from  the 
height  of  the  foot-piece,  which  also  protects 
the  contents  from  the  cooling  influence  of 
the  iron  bars  on  which  they  are  placed, 


DESCRIPTION  OF  IMPLEMENTS. 


83 


and  from  a too  direct  contact  with  the  colu 
draught.  Some  assay ers  use  an  extra 
cover  for  this  crucible,  a very  superfluous 
addition,  since  the  bottoms  of  the  old  cru- 
cibles answer  admirably  as  covers  to  the 
new.  As  mentioned  before,  these  also  are 
useless  after  once  having  been  employed, 
and  before  throwing  them  away  it  is  there- 
fore well  first  to  break  off  the  feet. 

Fig.  5 gives  a drawing  of  a Hessian  cru- 
cible, which  is  used  chiefly  in  the  assays  of 
iipn  ores.  These  are  imported  into  the 
United  States,  and  can  be  procured  in  al- 
most every  crockery  store.  Their  dimen- 
sions are  very  different,  and  so  contrived 
that  one  fits  into  the  next  in  size,  being 
in  sets  of  about  a dozen.  They  are  com- 
monly triangular  above,  and  round  below, 
as  shown  in  the  figure;  but  sometimes  they 
are  made  round  above  and  below,  and 
where  these  can  be  had,  they  should  be 
preferred.  If  they  cannot  be  procured, 
similar  crucibles  of  pure  clay  may  be  sub- 


34 


THE  ASSAYER’S  GUIDE. 


stitated,  and  in  fact  they  are  sometimes 
considered  preferable.  The  latter  are  then 
commonly  made  with  a foot-piece,  some- 
what as  in  fig.  4,  though  not  quite  so 
strongly  separated  from  the  main  bulk  of 
the  vessel.  These  or  the  Hessian  crucibles, 
as  will  be  seen  hereafter,  should  be  kept 
constantly  on  hand  thickly  coated  with 
charcoal.  They  are  prepared  in  this  man- 
ner. Charcoal  of  any  oak-wood,  except 
red-oak,  which  contains  much  oxide  of 
iron,  is  the  best  on  account  of  its  density. 
It  should  be  pulverized  with  the  utmost  care, 
since  a coarse  powder  will  never  furnish  a 
consistent  mass.  To  this  we  carefully  add 
water  until  we  procure  a tough  paste  or 
dough,  and  with  this  fill  the  crucible  very 
tightly,  always  ramming  down  every  new 
portion  introduced,  with  a pestle  or  piece 
of  wood.  When  the  whole  interior  is  filled 
up,  we  cut  out  a hole  in  the  middle  with 
a penknife,  leaving  a margin  of  about  half 


DESCRIPTION  OE  IMPLEMENTS. 


35 


an  inch  at  least,  below  and  all  round.  (See 
Assay  of  Iron  Ores.) 

Fig.  6 furnishes  a sketch  of  an  imple- 
ment, which,  though  not  immediately  ne- 
cessary, will  be  found  extremely  useful, 
inasmuch  as  it  tends  to  keep  up  order 
' and  accuracy,  great  requisites  for  an  able 
assayer.  As  will  be  seen  from  the  dif- 
ferent views  a and  b , it  consists  simply  of 
a piece  of  sheet-iron,  having  a wooden 
handle  and  several  semi-circular  cavities, 
the  number  of  which  may  vary  according 
to  the  number  of  assays  expected  to  be 
performed  at  once.  If  a large  muffle  is 
used  in  the  furnace,  it  is  well  also  to  have 
this  large;  and,  in  fact,  I would  suggest 
having  the  number  of  holes  in  each  row 
equal  to  the  number  of  cupels,  of  the  sort 
illustrated  in  fig.  1,  that  can,  without  col- 
lision, be  placed  across  the  muffle  from  side 
to  side.  (See  Silver  and  Gold  Ores.)  This 
pan,  or  whatever  we  may  otherwise  term 
it,  is  used  to  cool  the  buttons  of  metal  and 


36 


THE  ASSAYER  S GUIDE. 


their  surrounding  slag  after  having  oxi- 
dized part  of  the  lead,  &c.,  and  separated 
the  gangue-rock,  as  is  the  case  with  silver 
and  gold  (q.  v.)  The  holes  should  be  Ih 
inch  wide  and  £ inch  deep. 

Figs.  7 and  8 represent  two  different 
kinds  of  tongs.  Fig.  7 is  only  shown  in  a 
lateral  view,  since  its  characteristics  are 
thus  exhibited,  while  fig.  8 is  sketched 
from  above.  They  are  both  very  necessary 
in  the  progress  of  our  investigations.  The 
first  is  shaped  like  common  fire-tongs,  only 
that  the  ends,  instead  of  widening  into  a 
flat  circular  lobe,  are  bent  downward  like 
a poker,  thus  enabling  us  to  handle  the 
crucibles  with  great  care.  The  second 
tongs  has  each  piece  ending  in  a semi- 
circle, the  diameter  of  which  circle,  when 
united,  should  be  so  that  it  may  exactly 
embrace  the  lower  part  of  fig.  1.  It  is 
used  to  place  those  cupels  into  the  muffle, 
as  we  are  thereby  prevented  from  touch- 
ing the  contents.  In  using  this  latter  in- 


DESCRIPTION  OF  IMPLEMENTS. 


37 


strument  great  caution  should  be  taken  not 
to  upset  the  cupels.  Let  me  first  remark, 
that  on  introducing  the  cupels  into  the 
muffle,  we  always  commence  with  No.  1, 
i.  e.  first  assay  on  hand,  behind  on  the  left. 
It  may  seem  a very  superfluous  precaution 
to  dwell  thus  long  on  so  simple  a manipu- 
lation as  the  one  I am  now  describing; 
but  I know  from  experience,  how  many 
failures  carelessness  in  this  procedure  oc- 
casions to  the  uninitiated.  Let  us  now 
suppose,  that  we  have  the  crucible,  fig.  1, 
filled  with  the  powdered  mineral  to  be 
tested,  and  the  other  additions,  such  as 
lead  or  borax.  Grasping  the  cupel  firmly 
at  the  bottom,  we  lift  it  up  high,  so  that, 
when  pushed  into  the  mouth  of  the  muffle, 
it  is  a good  deal  above  its  floor,  and  cannot 
knock  against  it.  As  soon  as  it  is  within 
the  muffle,  without  leaving  hold  of  it,  and 
keeping  it  up  high,  we  hold  the  side  of  the 
tongs  up  against  the  side  of  the  muffle  to 
steady  them,  then  run  them  along  quietly 

4 


38 


THE  ASSAYER  S GUIDE. 


though  not  too  slowly,  for  that  only  causes 
the  hand  to  tremble,  until  the  crucible  is 
just  above  the  spot  where  we  intend  to 
place  it,  (when  once  down  it  should  never 
be  moved,)  and  then  slowly  lower  it,  not 
letting  go  till  it  stands  secure. 

These  tongs  should  be  made  light 
enough  conveniently  to  handle  them  with 
one  hand.  The  handles  are  made  of  some 
good  firm  wood,  though  No.  8 is  generally 
held  lower  down  than  the  handles,  and,  I 
may  add,  never  so  that  the  end  of  the 
tongs,  the  handle,  passes  under  the  arm, 
but  exactly  as  the  savages  hold  their  darts 
when  about  to  hurl  them.  It  may  seem 
awkward  at  first,  and  yet  I know  many 
accidents,  as  regards  the  assays,  having 
occurred  from  not  attending  to  it.  The 
length  of  the  tongs  ought  to  be  about  three 
feet.  It  may  be  well  to  supply  oneself 
with  a third  pair,  with  straight  and  rather 
pointed  ends. 


89 


II. 

Assay  of  Silver  Ores  by  Heat — Cwpellaticm. 

Silver  occurs  in  nature  chiefly  in  lead 
ores,  (galena,)  and  native,  as  in  the  Lake 
Superior  copper  mines,  or  less  commonly 
as  chloride  of  silver,  as  is  the  case  in  the 
extensive  mines  of  Chili.  The  following 
directions,  however,  refer  equally  to  the 
assays  of  all. 

As  with  all  minerals  to  be  investigated 
by  these  methods,  the  ore  must  previously 
be  reduced  to  the  finest  possible  powder,  for 
which  purpose,  where  many  assays  are 
made,  a large  iron  bowl  is  used  as  a 
mortar,  the  pestle  having  a wooden  handle 
attached  at  right  angles  to  the  iron  part, 
enabling  us  thus  to  employ  a much  greater 
force  than  if  it  were  straight,  as  commonly 
is  the  case.  The  usual  shape  of  a mortar, 


40 


THE  ASSAYER’S  GUIDE. 


used  in  kitchens  is  not  so  good,  for  its 
depth  prevents  its  being  cleaned  sufficiently 
to  insure  accuracy.  In  lieu  of  the  former, 
and  when  small  quantities  only  are  de- 
sired to  be  pulverized,  an  agate  mortar 
may  suffice.  Of  the  ore  we  weigh  off  one 
part,— about  3 grammes,  equal  to  46  grs. 
Troy,  (say  50  grs.)  is  a good  standard 
weight, — and  mix  it  with  ten  parts  by 
weight  of  pure  lead,  and  from  one-tenth  to 
one-fifth  part  of  borax,  in  the  manner  de- 
scribed below. 

The  lead  is  added  to  extract  all  impuri- 
ties, such  as  copper,  nickel,  &c.,  and  in 
cases  where  these  occur  in  great  abun- 
dance, should  be  used  in  the  proportions 
even  up  to  fifteen  and  twenty  parts,  though 
it  is  always  injurious,  and  tends  to  create 
a loss,  to  add  too  much. 

To  the  rules  for  testing  the  quality  of 
alloys  of  silver  and  copper,  will  be  found 
subjoined  a table  by  Erker,  to  regulate  this. 

The  lead  of  commerce  contains  many  im- 


ASSAY  OF  SILVER  ORES  BY  HEAT. 


41 


parities,  in  the  shape  of  other  metals, 
which,  since  silver  always  is  among  them, 
is  very  injurious  to  our  assays,  and  it  is 
therefore  necessary  to  obtain  a purer  article. 
At  silver  furnaces  lead  is  produced  as  an 
extra  product,  sufficiently  pure  for  our  pur- 
poses. That,  for  instance,  thus  procured 
from  the  smelting  works  at  Freiberg  in 
Saxony,  and  used  there  by  the  assayers, 
contains,  to  6.40000  parts  of  lead,  from 
0.00001  to  0.000015  parts  of  silver,  too 
slight  an  impurity  to  affect  the  result  of 
the  assay.  If  so  situated  as  not  to  be  able 
to  get  it  in  this  manner,  the  best  way  is  to 
reduce  it  by  a galvanic  process  from  acetate 
of  lead.  This,  the  sugar  of  lead  of  com- 
merce, we  can  readily  dissolve  in  luke- 
warm water,  after  which  we  should  filter 
off  the  solution,  and  introduce  a rod  of 
zinc,  by  which  process  all  the  lead  is  re- 
duced and  collected  round  that  metal. 
After  some  time  remove  it,  and  continue 
in  this  manner  until  all  the  lead  is  pre* 

4* 


42 


THE  ASSAYER’S  GUIDE. 


cipitated.  It  is  then  to  be  repeatedly 
washed  with  care  to  remove  the  acid,  and 
afterward  dried  between  blotting  paper. 
If  not  in  a sufficiently  pulverized  shape,  it 
need  only  be  shaken  a little  in  a towel  and 
finally  sieved.  A spoon  containing  a given 
amount — five  parts,  equal  to  250  grs.,  is  con- 
venient—is  used  to  measure  the  quantity 
for  each  assay,  thus  avoiding  the  tedium  of 
weighing  each  time,  a matter  of  consider- 
able consequence  in  an  assaying  office, 
where  frequently  hundreds  of  assays  are 
made  in  a day. 

The  vessel  into  which  the  mineral,  to- 
gether with  the  lead  and  borax,  is  placed, 
to  be  introduced  into  the  muffle  of  the  fur- 
nace, is  represented  in  fig.  1,  Plate  II.  (See 
the  description  given  a few  pages  back.) 
We  first  put  one-half  of  the  lead  to  be 
used  in  it,  and  on  the  top  the  silver  ore, 
mixing  the  two  with  great  care,  not  to 
spill  the  least  particle,  and  afterward 
cover  it  with  the  rest  of  the  lead,  and 


ASSAY  OF  SILVER  ORES  BY  HEAT. 


43 


sprinkle  the  borax  over  the  whole.  The 
latter  is  used  to  facilitate  the  melting  of 
the  lead,  and  to  produce  a good  slag. 
When  much  tin,  zinc,  or  lime  is  present 
in  the  ore,  the  borax ' should  be  increased 
in  quantity  up  to  the  largest  amount  before 
mentioned. 

If  we  desire  to  test  ores  containing  very 
little  silica,  and  our  crucibles  are  not  as 
perfect  as  we  might  wish  them  to  be,  it  is 
very  advisable  to  make  use  of  some  quartz 
or  glass-powder,  to  be  added  immediately, 
or,  better  still,  when  the  slag  is  forming, 
and  the  process  of  calcining  is  thus  at  an 
end. 

We  should,  for  the  sake  of  economy  with 
the  fuel,  make  several  assays  at  once,  and 
always  five  or  six  of  each  ore,  afterward 
taking  the  average,  and  thus  regulating 
our  own  labour. 

After  previously  firing  the  furnace,  and 
bringing  the  muffle  to  a regular  and  con- 
stant red-heat,  we  may  introduce  the  cru- 


44 


THE  ASSAYER’S  GUIDE. 


cibles.  To  quicken  the  melting  of  the 
lead,  we  place  some  pieces  of  well-dried 
charcoal,  which  should  always  be  kept  on 
hand,  in  front  of  the  crucibles.  Vapours 
will  be  observed  to  be  emitted,  caused  by 
the  discharge  of  volatile  substances.  The 
door  of  the  muffle,  previously  closed, 
should  be  kept  perfectly  open  as  soon  as 
the  operation  of  calcining  or  roasting  the 
ore  has  properly  commenced,  to  admit 
fresh  air,  and  prevent  the  heat  from  in- 
creasing too  much. 

This  process  generally  lasts  about  twenty 
minutes,  after  which,  by  introducing  fresh 
coals  into  the  muffle  and  again  closing  the 
door,  we  raise  the  heat,  and  continue  it 
sufficiently  long  to  let  the  slags  collect  and 
flow  easily,  so  as  to  make  a crust  round  the 
white-hot  metal.  When  not  employing  a 
sufficiently  high  temperature,  the  slag  will 
remain  thick  or  tough,  and  retain  the 
metallic  alloy  of  silver  and  lead  in  small 
particles  disseminated  throughout  the  mass. 


ASSAY  OF  SILFER  ORES  BY  HEAT. 


45 


From  the  circular  portion  of  argentiferous 
lead,  which  appears  to  be  in  a constant 
rotary  motion  in  the  centre  of  the  slag, 
vapours  of  lead  rise  incessantly.  The  time 
that  should  be  occupied  by  this  process  of 
melting  varies  much  according  to  the 
character  and  quality  of  the  ore,  which 
sometimes,  though  rarely,  may  even  require 
something  more  than  half  an  hour.  Gene- 
rally much  less  time  is  wanted  with  a good 
fire,  and  the  assayer  can  always  see  at  what 
time  the  encircling  slag  has  been  properly 
separated  from  the  metal,  and  even  with 
very  little  practice  is  enabled  to  regulate  it. 
We  now  again  open  the  muffle,  and  by 
oxidizing  some  more  lead  during  the  space 
of  ten  minutes,  cover  the  metal  entirely, 
and  after  that,  once  more  apply  a strong 
heat  for  a few  minutes  to  make  the  slags 
flow  easy,  and  then  taking  out  the  crucibles, 
pour  the  whole  contents  into  the  different 
hollows  of  the  iron  plate,  illustrated  by  fig. 
6,  Plate  II.  This  should  be  done  very 


46 


THE  ASSAYER’S  GUIDE. 


quickly,  for  otherwise  the  lead  will  not 
collect  in  one  button,  but  be  distributed 
in  small  particles  all  over  the  molten  slag 
as  above.  A little  practice  will  soon  accus- 
tom any  one  to  all  these  operations. 

On  cooling,  with  a stroke  or  two  of  the 
hammer  we  separate  the  slags  from  the 
metallic  buttons,  and  with  a few  more 
easily  shape  the  latter  into  cubes  as  regular 
as  possible. 

The  crucibles  shown  in  fig.  2,  Plate  II. 
come  into  use  at  this  part  of  the  assay.  If 
well  made  and  dried,  they  should  be  very 
porous,  and  so  friable  as  to  be  crushed 
between  the  fingers  with  ease. 

In  these  cupels  we  expose  the  metal 
cubes  to  a moderate  red-heat,  which  we  are 
enabled  to  regulate  by  inserting  cold  pieces 
of  pottery — old  crucibles  will  be  found  very 
serviceable— and  leaving  the  furnace  open. 
The  rising  vapours  are  from  the  lead,  and 
continue  until  that  peculiar  bright  flash  of 
light  is  observed,  termed  silberblick , (silver- 


ASSAY  OF  SILVER  ORES  BY  HEAT.  47 

gleam,)  in  German  mining  and  smelting 
technology,  and  from  which  we  know  that 
the  silver  is  pure.  The  utmost  attention 
should  be  paicT  to  this  part  of  the  assay,  to 
ascertain  the  moment  when  this  occurs. 
The  coolers  are  then  carefully  removed,  the 
aperture  closed,  and  the  most  intense  heat 
possible  kept  up  for  a few  moments.  To 
do  this  well  is,  I may  say,  the  chef  d' oeuvre 
of  an  assayer,  and  on  it  depends,  in  a great 
measure,  the  accuracy  of  the  assay ; for  the 
silver,  when  pure,  requires  a much  greater 
heat  to  bring  it  to  the  melting  point  than 
when  it  contains  even  a very  small  admix- 
ture of  lead ; and  for  this  reason,  if  we  do 
not  instantly  elevate  the  temperature  when 
the  ceasing  of  the  rainbow  colours  and  the 
bright  light  of  the  globule  of  pure  silver 
inform  us  that  all  the  lead  has  left, — then 
the  silver  would  cool  suddenly,  and,  of 
course,  quicker  at  the  surface  than  in  the 
interior  or  at  the  bottom,  and  by  this 
subitaneous  contraction  cause  a spattering 


48 


THE  ASSAYER’S  GUIDE. 


motion  of  the  yet  unconsolidated  particles, 
and  be  productive  of  great  loss  to  the 
assay. 

There  is  an  old  adage  current  among 
German  smelters  and  assayers, — probably 
known  to  all  who  may  have  had  the 
advantage  of  studying  this  art  in  that 
country,  where  it  has  been  brought  to  such 
perfection,— which,  since  it  is  many  centu- 
ries old,  shows  how  long  it  has  been  re- 
garded as  the  great  aim,  in  this  mode  of 
testing  silver  ores,  to  keep  up  a moderate 
temperature  as  long  as  any  lead  is  left,  and 
to  apply  intense  heat  as  soon  as  all  has  de- 
parted. I insert  them  here  : 

u Kiihl  getrieben,  heisser  Blick 
1st  des  Probierer’s  Meisterstiick.” 

In  English  it  would  be : To  evaporate 
coolly  and  to  use  heat  when  pure,  is  the 
masterpiece  of  an  assayer. 

When  the  buttons  of  pure  silver  have 
cooled,  we  grasp  them  firmly  with  a pair 
of  pincers,  tight  enough  to  compress  the 


ASSAY  OF  SILVER  ORES  BY  HEAT.  49 

sides,  thus  exposing  the  bottom  more,  and 
with  a wire  brush  remove  the  adhering 
particles  of  litharge,  and  dust  of  the  cupel. 
Turning  them  half  round  so  as  to  make 
the  base  a square,  we  repeat  the  operation, 
and  then  weigh,  but  only  when  quite  cold, 
since  otherwise  the  heat,  by  increasing 
the  bulk,  might  tend  to  create  a varia- 
tion. 

The  silver  produced  in  this  manner,  it 
should  be  remarked,  is  not  perfectly  pure, 
chemically  speaking,  but  the  slight  impu- 
rities are  too  insignificant  to  deserve  any 
attention  from  an  assayer,  who  has  nothing 
but  technical  purposes  in  view,  though 
they  might  require  it  from  a scientific 
cnemist ; and  for  this  latter  reason,  I have 
thought  proper  in  the  third  chapter  to  sug- 
gest a method  to  ascertain  the  exact 
amount  of  silver  in  this  button,  should  it 
be  deemed  necessary,  though,  I must  add, 
that  such  precision  can  only  be  required 
at  mints,  if  the  investigations  are  not  con- 

5 


50 


THE  ASSAYER’S  GUIDE. 


ducted  for  science’  sake,  in  which  case,  the 
wet  process  would,  of  course,  be  preferred 
from  the  beginning. 

Besides  this,  small  inaccuracies  in  the 
shape  of  losses,  as  has  already  been  re- 
marked, cannot  be  averted,  even  though 
the  assay  be  performed  with  the  greatest 
care,  as  the  evaporating,  or  rather  oxid- 
izing lead  probably  carries  off  small  par- 
ticles of  silver,  particularly  when  too  much 
heat  is  used  during  that  process.  It  is  im- 
possible to  give  any  perfect  rules  how  to 
obviate  such  faults,  since  so  much  depends 
on  the  care  and  attention  paid,  as  well  as 
on  the  acquired  practice  and  innate  prac- 
tical skill  of  the  assay er ; yet,  pre-supposing 
all  this  as  perfect,  the  Parisian  mint  has 
established  a table  to  regulate  their  assays, 
which  will  be  found  on  pages  52  and  53. 
From  this  it  is  seen  that  the  different  losses 
with  different  quantities  of  silver  vary  con- 
siderably, nor  is  the  loss  a per-centage, 
being  greatest  where  the  original  or  true 


ASSAY  OF  SILVER  ORES  BY  HEAT. 


51 


amount  of  silver  in  the  ore  or  alloy  is 
seven  hundred. 

This  table  should  always  be  referred  to, 
as  it  enables  us  to  calculate  the  true 
amount  of  silver,  and  to  rectify  those  un- 
avoidable faults  which  may  be  occasioned 
by  the  lead  carrying  off  portions  of  the 
silver  entirely,  or  else  drawing  them  along 
with  it  into  the  pores  of  the  crucible. 


52 


III. 

A Table  to  rectify  the  Loss  incurred  during 
the  Silver  Assay. 


Real  amount  of 
silver. 

Amount  of  silver 
found  by  the  assay. 

Loss  during 
process. 

1000 

998*97 

108 

975 

973*24 

l-7o 

950 

947*50 

2-50 

925 

921*75 

8-25 

900 

896*00 

4-00 

875 

870*93 

4 07 

850 

845*85 

4-15 

825 

820*78 

4-22 

800 

795*70 

4-30 

775 

770*59 

4-41 

750 

745*48 

4-52 

725 

720*36 

4-64 

700 

695*25 

4-75 

675 

670*27 

4-73 

650 

645*29 

4-71 

625 

620*30 

4-70 

600 

595*32 

4-68 

575 

570*32 

4-68 

LOSS  DURING  THE  SILVER  ASSAY. 


53 


Real  amount  of 
silver. 

Amount  of  silver 
found  by  the  assay. 

Loss  during  the 
process. 

550 

545-32 

4-68 

525 

520-32 

4-68 

500 

495-32 

4-68 

475 

470-50 

4-50 

450 

445-69 

4-31 

425 

420-87 

4-13 

400 

396-05 

3-95 

375 

371-39 

3-61 

350 

346-73 

3-27 

325 

322-06 

2-94 

300 

297-40 

2-60 

275 

272-42 

2-58 

250 

247-44 

2-56 

225 

222-45 

2-55 

200 

197-47 

2-53 

175 

172-88 

2-12 

150 

148-30 

1-70 

125 

123-71 

1-29 

100 

99-12 

0-88 

75 

74-34 

0-66 

50 

49-56 

0-44 

25 

24-78 

0-22 

5* 


m 


IV. 

Gay-Lussacs  Process  for  assaying  Silver 
Alloys . 

This  modus  ojperandi  is  one  which,  from 
its  very  simplicity  and  shortness,  almost 
necessarily  insures  success,  but  it  is  only 
intended  for  alloys,  such  as  coins,  and  can, 
therefore,  if  applied  to  ores,  only  be  used 
to  ascertain  the  real  amount  of  silver  in 
the  button  produced  in  the  last  assay, 
which,  as  already  observed,  contains  a very 
minute  amount  of  spurious  metals  in  an 
alloyed  state. 

It  was  proposed  by  Gay-Lussac,  and 
from  the  indubitableness  of  its  results, 
has  since  been  introduced  in  France,  and 
most  parts  of  Germany,  to  regulate  the 
assays  of  the  mint. 

They  dissolve  a given  weight  of  the 


GAY-LUSSAC  S PKOCESS. 


55 


alloy  in  nitric  acid,  and  then  find  a solu- 
tion of  common  salt — of  which,  a large  as- 
sortment of  different  known  degrees  of 
strength  is  constantly  kept  on  hand  in 
bottles— sufficiently  strong  to  precipitate 
all  the  silver  as  chloride  of  silver,  when 
used  in  a certain  established  quantity.  In 
this  manner,  the  amount  of  silver  is  found 
by  the  quantity  of  salt  used.  (Gay-Lussac 
on  Assays  of  Silver,  q.  v.) 


56 


V„ 

Assay  of  Gold  Ores  by  Heat. 

Those  properties  of  silver,  which  enable 
us  to  assay  its  ores  by  the  process  of 
cupellation,  are  so  equally  characteristic 
of  gold  and  its  ores,  that,  were  I to  dwell 
more  at  length  on  this  first  part  of  the 
operation,  it  would  be  a mere  repetition  of 
what  has  been  said  under  the  head  of 
Silver,  and  therefore  I shall  only  refer  the 
reader  to  the  remarks  given  above. 

When,  however,  that  process  is  com- 
pleted, and  when  therefore  with  silver  we 
would  have  procured  the  final  result,  the 
real  gold  assay  only  commences,  for  gold, 
though  always  native,  contains  silver,  pla- 
tinum, &c. 

I must  remark  that,  since  gold  ores  are 
almost  invariably  excessively  poor,  com- 


ASSAY  OF  GOLD  ORES  BY  HEAT. 


57 


pared  with  those  of  other  metals,  we 
should  arrange  our  assays  accordingly, 
and  commence  writh  a larger  amount  of 
ore  than  is  necessary  in  other  cases.  For 
this  purpose  it  is  common  to  begin  with 
six  different  parts  of  ore  of  50  grs.  each, 
which,  after  being  mixed  with  lead  and 
borax  as  with  silver,  are  committed  to 
the  muffle  in  as  many  separate  crucibles. 
The  products  are  then  melted  up  into  two 
buttons,  in  two  different  cupels  of  the  same 
kind,  and  these  again  in  the  process  of 
extracting  the  lead  are  concentrated  into 
one.  Of  course,  when  the  assay  is  finished 
we  are  obliged  to  divide  the  produce  by  six 
to  ascertain  the  per-centage  amount  of  gold 
in  the  specimen  under  examination. 

After  having  proceeded  thus  far,  it  is  neces- 
sary to  procure  some  perfectly  pure  silver, 
for  which  we  have  the  following  methods: 
first,  by  producing  chloride  of  silver,  which 
is  done  by  precipitating  the  silver  from  the 
nitric  acid  solution,  with  muriatic  acid,  and 


58 


THE  ASSAYER’S  GUIDE, 


melting  it  in  a porcelain  crucible,  with  pot- 
ash; chloride  of  potash  and  the  pure  silver 
being  thus  formed : or  secondly  by  the 
galvanic  process,  the  virgin  metal  being 
thus  collected  round  a rod  of  zinc  immersed 
in  the  acid  (nitric)  liquid  from  which, 
as  above,  the  silver  has  been  extracted  by 
adding  muriatic  acid,  but  which  precipitate 
must  remain  in  the  same  vessel.  The 
silver  is  then  preserved  in  the  shape  of 
filings. 

It  is  necessary  to  make  use  of  this  silver 
whenever  the  quantity  of  gold  in  the  last 
produced  button  is  more  than  one  fourth, 
(hence  the  term  quartation)  since  experi- 
ence has  shown  that  if  there  are  not  at  least 
about  three  quarters  the  amount  of  silver 
(rarely  the  case  with  ores)  in  this  alloy, 
the  gold  would  protect  the  particles  of 
silver  from  the  action  of  the  acid,  which, 
as  will  become  evident  from  the  sequel, 
would  prove  fatal  to  our  investigations. 

Of  the  pure  silver,  two  and  a half  times 


ASSAY  OF  GOLD  ORES  BY  HEAT. 


59 


the  weight  of  the  buttons  of  impure  gold, 
and  about  half  the  weight  of  both  in 
pure  lead,  should  be  melted  up  with  them 
in  one  crucible,  (fig.  2,  Plate  II.)  This 
single  button  of  gold  and  silver  alloy  is  to 
be  hammered  flat  on  a little  steel  anvil, 
and  slightly  curved,  as  this  shape  will 
allow  it  more  easily  to  pass  through  the 
mouth  of  a little  vial,  in  which  it  is  now 
placed  to  be  boiled  with  nitric  acid  (2 
drams)  of  from  1 to  3 specific  gravity. 
The  vial  should  be  round  at  the  bottom 
as  this  is  performed  over  a spirit-lamp. 
We  allow  the  liquid  to  boil  until  the 
yellowish  vapours  of  nitrous  acid  gas  have 
ceased  to  be  emitted.  The  gold  is  then 
pure,  and  requires  only  to  be  boiled  a 
couple  of  times  in  water  to  remove  the  acid, 
and  then  to  be  heated  to  redness  to  evapo- 
rate the  water,  to  enable  us  to  weigh  it, 
which,  as  with  all  other  assays,  should 
never  be  done  till  the  metal  is  perfectly 
cold. 


60 


THE  ASSAYER’S  GUIDE. 


If  a small  portion  of  platinum  be  in  the 
ore,  it  will  be  found  in  the  nitric  acid 
solution  of  silver.  (See  Platinum.) 

The  original  amount  of  silver  may  be 
ascertained  by  deducting  the  weight  of  the 
gold  from  the  button  produced  before  the 
other  pure  silver  was  added. 


Assay  of  Gold  Ores  by  Amalgamation . 


This  method  is  founded  on  the  fact,  that 
gold  unites  with  quicksilver  to  form  an 
amalgam,  for  thus  the  alloys  of  mercury 
and  other  metals  are  termed.  It  is  one 
that  may  answer  for  peculiar  circum- 
stances, though  it  is  not  accurate  enough 
to  serve  as  a regular  dokimastic*  test,  since 
lead  and  silver  also  produce  amalgams. 

We  require  pure  mercury  for  this  pur- 
pose; and  as  the  quicksilver  of  commerce 
generally  contains  some  lead,  we  must  pu- 
rify it  by  pressing  it  through  a piece  of 
buckskin. 

The  powdered  gold  ore,  which  ought 


* A technical  term,  derived  from  the  Greek  verb 
to  try,  to  test  the  purity  of  a thing. 


62 


THE  ASSAYER’S  GUIDE. 


first  to  be  reduced  in  volume  by  washing, 
is  brought  in  contact  with  the  quicksilver, 
the  sand  or  gangue-rock  removed  by  sift- 
ing the  mass  through  a coarse  cloth;  after 
which,  by  forcing  the  quicksilver  through 
some  buckskin,  the  amalgam  is  retained. 

By  evaporating  the  mercury  in  an  iron 
spoon  over  a lamp,  the  gold  is  procured, 
which  will,  however,  still  be  found  to  con- 
tain silver  or  lead,  if  these  occur  in  the 
ore. 


63 


VII. 

/ 

Assay  of  Gold  by  Washing . 

This  is  a way  of  ascertaining  the  ap- 
proximate value  of  a gold  ore,  which  hardly 
deserves  being  called  an  assay,  although, 
with  an  experienced  hand,  tolerable  accu- 
racy may  be  attained. 

. It  is  based  on  the  fact,  that  gold  is  much 
heavier  than  quartz  or  other  ganguerock, 
and  therefore  the  rock  should  be  well 
pounded  for  this  operation. 

The  process  is  precisely  the  same  as  that 
used  to  extract  gold  from  the  sand  of  river 
beds,  and  which  is  now  so  extensively  em- 
ployed in  California.  Even  the  vessels 
used  are  frequently  of  the  same  kind, 
though  it  is  better  to  have  a small  glass 
cylinder,  about  three  times  the  length  of 
the  part  that  will  be  occupied  by  the  ore, 


64 


THE  ASSAYER’S  GUIDE. 


and  three-quarters  of  an  inch  in  diameter, 
closed  at  the  end,  like  a common  chemical 
test-glass.  I would  suggest,  if,  where  used, 
the  gangue-rock  or  sand  be  always  of  the 
same  kind,  having  a mark  round  the  tube 
made  with  a slight  scratch  of  the  diamond, 
up  to  where  a certain  quantity  by  weight 
of  the  ore  would  reach.  One  hundred 
grains  would  not  be  too  much,  if,  for  in- 
stance, the  rock  is  quartz;  and  it  is  also 
the  most  convenient  amount,  from  the 
facility  thus  afforded  in  afterward  calcu- 
lating the  per-centage.  Under  circum- 
stances where  we  have  to  deal  with  ores 
in  which  the  original  rock  is  not  always 
the  same,  it  would  be  well  to  have  several 
such  tubes,  to  each  of  which  its  peculiar 
rock  might  be  allotted;  or  one  with  dif- 
ferently marked  lines.  In  this  manner, 
one  such  line  might  indicate  the  part  of 
the  tube  which  would  be  filled  by  a hun- 
dred grains  of  the  quartzose  ore,  another 
the  portion  which  would  be  occupied  by 


ASSAY  OF  GOLD  BY  WASHING. 


65 


the  same  weight  of  a talcose  one,  and  so 
on.  The  lines  will  vary  in  height  as  the 
ratio  of  the  various  specific  gravities  of  the 
respective  ores. 

When  the  properly  pulverized  ore  has 
been  placed  in  the  glass  tube,  the  latter 
should  be  filled  up  two-thirds  with  water, 
and  tightly  corked ; after  which,  by  repeated 
shakings,  the  gold  will  be  collected  below. 
By  careful  decanting  and  continual  shak- 
ing, we  can  remove  the  sand  and  particles 
of  rock,  and  retain  the  gold  as  a matter  of 
course,  though  only  in  its  natural,  alloyed 
state. 

This  method  will  be  found  to  be  a con- 
siderable improvement  on  the  washing  in 
pans.  If  the  ore  contains  iron  pyrites,  it 
is  best  to  calcine  it  first,  though  carefully, 
so  that  no  gold  is  carried  off  mechanically 
by  the  gases  formed. 


6* 


66 


VIII. 

Assay  of  Gold  Ores  hy  a Wet  Process . 

Although  I have  tried  to  make  it  a 
point  to  introduce  as  few  wet  processes  as 
possible  into  this  treatise,  I now  venture 
to  give  directions  for  one  which  will  be 
found  very  available  to  ascertain  the  true 
amount  of  gold,  when  the  gold  has  been 
extracted  in  its  natural  state  by  the  last- 
given  methods.  It  is  characterized  by  the 
ease  with  which  it  can  be  performed. 

The  residue  of  alloyed  gold  produced  by 
washing  the  ore  or  sand  should  be  sub- 
mitted to  the  action  of  concentrated  aqua 
regia,  (consisting  of  from  three  to  four  parts 
of  muriatic  acid,  to  one  of  nitric,)  by  which 
all  the  gold  is  extracted.  All  the  plati- 
num, if  that  metal  be  present,  will  be  pre- 
cipitated as  below  from  this  liquid. 


ASSAY  OF  GOLD  ORES  BY  A WET  IROCESS.  67 

The  solution  should  then  be  filtered  off 
with  the  greatest  care,  water  being  after- 
ward poured  on  to  wash  the  insoluble 
parts,  and  to  procure  the  whole  of  the  dis- 
solved gold.  Sal-ammonia  is  then  to  be 
added,  and  if  causing  a precipitate,  the  in- 
fusion filtered  again.  This  latter  is  then 
evaporated  to  dryness,  and  alcohol  of  0*84 
specific  gravity  repeatedly  added,  and  after 
digesting  poured  off,  until  no  more  coloured 
by  the  dissolving  chloride  of  gold.  Iron 
vitriol  (copperas)  in  solution,  if  poured 
into  it,  will  precipitate  the  pure  gold  as  a 
brown  powder,  which  may  then  be  filtered, 
washed,  heated  to  redness,  and  weighed. 


68 


IX. 

Assay  of  Silver  Coins , or  Alloys  of  Silver  and 
Copper. 

As  a matter  of  course,  with  these  alloys 
it  is  not  necessary  to  perform  the  operation, 
which  is  done  with  the  ores,  of  first  sepa- 
rating the  gangue-rock.  We  proceed  with 
the  cupellation,  as  soon  as  by  prior  tests  we 
have  ascertained  the  probable  amount  of 
silver  and  copper.  To  know  this  more 
accurately  no  method  exists,  except  a 
previous  hasty  cupellation,  though  to  a 
practised  assayer  it  is  cognisable  from  the 
greater  specific  gravity,  whiter  colour,  and 
increased  malleability  of  the  more  argen- 
tiferous alloys.  It  is  necessary  previously 
to  become  acquainted  with  this,  as  the 
quantity  of  lead  must  be  taken  accordingly. 
By  adding  too  much,  a loss  of  silver  is 


ASSAY  OF  SILVER  C;  INS. 


69 


incurred,  while,  if  too  little  is  used,  we  will 
not  be  able  to  procure  a pure  silver  button, 
as  not  all  the  copper  will  pass  over  into  the 
litharge. 

The  table  to  regulate  the  requisite  quan- 
tity of  lead,  was  calculated  by  Erker. 
Still  later,  D’Arcet  arranged  another,  which, 
though  less  simple,  experience  has  shown 
to  be  no  more  accurate,  and  it  is  for  this 
reason  that  I have  subjoined  the  former. 


32  parts  of  the  Alloy  containing 

Require  in 
parts  of 
Lead. 

Relative  quanti- 
ties of  Copper 
to  Lead. 

Parts  in  Silver. 

Parts  in  Copper. 

31 

1 

128 

1 

: 128 

80 

2 

192 

1 

: 96 

28 

4 

256 

1 

: 64 

24-26 

8-6 

320 

1 

: 40-53 

18-24 

14-8 

448 

1 

: 32-54 

8-16 

24-16 

480 

1 

: 20-30 

2-8 

30-24 

512 

1 

: 16-21 

From  this  table,  it  is  evident  that  the 
relative  amount  of  lead  should  decrease  as 
the  copper  increases,  although  the  more 
copper  the  alloy  contains,  the  more  lead 
should  be  used. 


70 


THE  ASSAYER’S  GUIDE. 


The  only  way  to  pulverize  a coin  or 
alloy  is  to  file  off  small  portions.  About 
a gramme  or  fifteen  grains  of  the  filings 
should  be  carefully  weighed  off,  wrapped 
in  paper,  (satin  paper  is  the  best,  giving 
little  ashes,)  to  prevent  small  particles 
from  being  lost,  and  placed  in  the  muffle 
furnace  on  the  cupel,  fig.  2.  When  the 
paper  is  burnt  to  ashes,  the  lead  is  added 
according  to  the  table.  The  rest  of  the 
assay  is  exactly  as  with  silver  ores.  As 
long  as  lead  and  copper  are  being  oxidized, 
no  severe  heat  should  be  employed,  which 
is,  however,  done  as  soon  as  the  bright 
flash  appears. 

The  alloy  or  coin  may  also  be  treated 
according  to  Gay-Lussac’s  process,  already 
described.  Having  thus  ascertained  the 
amount  of  silver,  we  are  easily  enabled  to 
calculate  that  of  the  copper,  by  subtraction. 


71 


X. 

/ 

Assay  of  Gold  Goins , or  Alloys  containing 
Gold , Silver , and  Copper. 

Before  making  the  regular  assay,  it  is 
necessary  to  ascertain  the  probable  contents 
of  the  alloy,  as  with  silver.  The  method 
commonly  used  is  the  touchstone  or  hesanite 
test,  the  same  employed  by  goldsmiths 
when  purchasing  coin  or  bullion.  A dark 
fine-grained  basalt  or  siliceous  slate  is  re- 
quired, and  on  this  a line  is  drawn  with  the 
gold  coin.  Those  whom  business  has  fre- 
quently brought  in  contact  with  such 
alloys  are  generally  able  to  judge  pretty 
accurately  by  this  alone,  as  the  purer  it  is, 
the  brighter  the  yellow,  silver  making  it 
whitish,  copper  of  a redder  hue.  To  carry 
this  test  out  farther,  the  mark  is  moistened 
with  an  acid,  which,  dissolving  the  baser 


72 


THE  ASSAY E-Il’s  GUIDE. 


metals,  leaves  the  gold  in  its  virgin  state. 
This  acid  consists,  in  thousand  parts,  of 

784  parts  of  pure  nitric  acid,  of  1.340  specific  gravity. 

16  “ “ u muriatic  acid,  of  1.173  spec.  gray. 

200  u u u distilled  water. 

1000 

As  with  gold  ores,  several  assays  should 
be  made  at  once,  to  regulate  one  another. 
When  some  of  the  alloy  has  been  filed  off 
• — too  small  pieces  ought  not  to  be  taken, 
on  account  of  their  liability  to  be  blown 
away- — these  particles  should  be  carefully 
brushed,  to  remove  the  fine  dust,  which 
might  otherwise  only  drop  off  after  weigh- 
ing, and  thus  cause  a decided  loss. 

For  the  assays,  5 grains  are  used  in  each, 
and  the  value  of  the  gold  is  afterward  given 
in  carats  fine,  pure  gold  being  reckoned  at 
24  carats  fine.  In  this  way  an  alloy 
containing  91.666  per  cent,  of  gold  will  be 
22  carats  fine,  or  in  other  words,  it  contains 
| or  ~ of  pure  gold  to  ^ of  the  alloyed  metal. 


ASSAY  OF  GOLD  COINS. 


73 


After  having  weighed  off  the  above 
quantity  of  the  gold  to  be  tested,  three 
times  the  weight  of  the  expected  amount 
of  gold,  as  ascertained  by  the  prior  inves- 
tigations, are  taken  in  pure  silver.  Some 
deem  two  and  a half  sufficient.  The  gold 
and  the  silver  are  then  carefully  wrapped 
in  a piece  of  paper. 

It  is  now  necessary  to  ascertain  the 
required  quantity  of  pure  lead,  which 
varies  according  to  the  per-centage  of  cop- 
per in  the  coin  or  alloy.  As  this  metal 
has  a much  greater  affinity  for  gold  than 
for  silver,  it  is  much  more  difficult  to  sepa- 
rate it  from  its  alloys  with  the  former 
than  with  the  latter,  and  for  this  reason 
the  lead  used  should  be  about  twice  as 
much  as  would  be  necessary,  were  we 
assaying  a coin  consisting  of  silver  and 
copper.  The  following  table  is  given  by 
D’Arcet  to  regulate  the  amount  to  be 
used : — 


7 


74 


THE  ASSAYER’S  GUIDE. 


If  the  contents 
allce 

In  1,000  parts. 

of  gold  in  the 
is 

In  carats  fine. 

The  quanti- 
ty of  lead  re- 
quired is 

Relative  quantity 
of  lead  to  the 
copper. 

1.000 

24. 

1 

0 

0.900 

21.6 

10 

100.000  to  1 

0.800 

19.2 

16 

80.000  to  1 

0.700 

16.8 

22 

73.333  to  1 

0.600 

14.4 

24 

60.000  to  1 

0.500 

12.0 

26 

52.600  to  1 

0.400 

9.6 

34 

56.666  to  1 

0.300 

7.2 

34 

48.571  to  1 

0.200 

4.8 

34 

42.500  to  1 

0.100 

2.4 

34 

37.777  to  1 

As  with  silver  assays,  if  too  much  be 
employed,  it  will  produce  a loss,  while  too 
little  would  not  extract  all  the  copper. 

The  lead  is  first  placed  in  the  cupel, 
(fig.  2,)  and  only  when  the  process  of  oxid- 
ation has  commenced,  is  the  paper  contain- 
ing the  gold  and  silver  to  be  added.  The 
rest  is  performed  exactly  as  with  gold  ores. 
The  button  should  be  hammered  to  a very 
thin  sheet,  before  being  submitted  to  the 
nitric  acid;  and  to  do  this  well,  it  should 
be  perfectly  cold,  as  otherwise  marginal 


ASSAY  OF  GOLD  COINS. 


75 


cracks  are  often  produced,  which  again 
may  be  productive  of  loss. 

It  may  not  be  quite  out  of  place  here  to 
give  the  contents  of  pure  gold  in  carats 
fine,  and  the  weight  and  value  of  the 
United  States  gold  coins,  as  well  as  of 
those  of  other  nations,  made  legal  tender 
with  us,  according  to  the  act  of  Congress 
of  June,  1834.  By  an  act  of  that  date, 
the  standard  value  of  our  eagles,  and  other 
gold  coins  in  proportion,  was  changed;  as 
will  be  seen  from  the  subjoined  table, 
which  has  been  taken  from  the  American 
Almanac  of  1835,  page  153. 


Names  of  Coins,  and  Countries  where 
minted. 

Weight. 

Cont. 
in  pure 
Gold. 

Assay. 

NewValue 
since  July 
31, 1831. 

United  States.  Eagle  coined  be- 

dwt. grs. 

grs. 

ear.  grs. 

dol.  cts.  m. 

fore  July  31,  1834 

Do.  since  then,  double  and 

11  6 

247-5 

22  — 

10  66  5 

shares  in  proportion 

Brazil , Johannes,  * in  propor.. 

10  18 
18  — 

232 

21  21* 
21  3| 

10 

17  6 4 

Dobraon  

34  12 

759 

22  — 

32  70  6 

Dobra  

18  G 

401-5 

22  — 

17  30  1 

Moidore,  * in  proportion 

6 22 

152-2 

22  — 

6 55  7 

Crusado  

16* 

14-8 

21  3$ 

— 63  8 

: Colombia.  Doubloon 

17  9 

300-5 

20  3 

15  63  5 

England.  Guinea,  * in  propor. 

5 8* 

118-7 

22  — 

5 7 5 

, Sovereign  do 

5 2* 

113-1 

22  — 

4 83  8 

76 


THE  ASSAYER  S GUIDE. 


Names  of  Coins,  and  Countries  where 
minted. 

Weight. 

Cont. 
in  pure 
Gold. 

Assay. 

New  Value 
since  July 
31,  1834. 

dw. 

grs. 

grs. 

car. 

• grs. 

dol. 

cts. 

m. 

England.  Seven  Shilling  Piece. 

1 

19 

39-6 

22 

1 

69 

8 

France.  Double  Louis  coined 

before  1786 

10 

11 

224*9 

21 

2 

9 

68 

8 

Louis  do 

5 

112*4 

21 

2 

4 

84 

3 

Double  Louis  coined  since 

1786 

9 

20 

212*6 

21 

9 

16 

2 

Louis  coined  since  1786 

4 

22 

106*3 

21 

4 

4 

58 

1 

Double  Napoleon,  or  40  frs... 

8 

7 

179 

21 

7 

70 

3 

Napoleon,  or  20  francs 

4 

H 

89*7 

21 

2* 

3 

86 

6 

Mexico.  Doubloons,  shares  in 

proportion 

17 

9 

360*5 

20 

3 

15 

53 

5 

Portugal.  Dobroan .. 

34 

12 

759 

22 

32 

70 

6 

Dobra 

18 

6 

401*5 

22 

17 

30 

1 

Johannes 

18 

__ 

17 

6 

4 

Moidore,  J in  proportion 

6 

22 

152*2 

21 

CO 

6 

55 

7 

Piece  of  16  Testoons,  or  1600 

rees 

2 

6 

49*3 

22 

2 

12 

1 

Old  Crusado,  or  400  rees 

— 

15 

13*6 

21 

8| 

— 

58 

8 

New  do.  or  480  rees 

— 

161 

14*8 

21 

8* 

— 

63 

7 

Milree  coined  in  1755 

— 

19f 

18*1 

21 

3§ 

— 

78 

New  Dobra... 

17 

6 

22 

16 

25 

3 

Joannese,  double  in  propt. ... 

9 

6* 

21 

3f 

8 

76 

3 

i do. 

4 

15 

21 

3f 

4 

37 

1 

Piece  of  12  Testoons,  or  1200 

rees 

1 

16i 

21 

1 

57 

4 

Do.  of  8 Testoons,  or  800  rees. 

1 

21 

3-f 

1 

12 

- 

Spain.  Quadruple  Pistole,  or 

Doubloons,  1772,  double, 

single,  and  shares  in  propt. 

17 

8* 

37*2 

21 

2* 

16 

3 

8 

Doubloon,  1801 

17 

9 

360*5 

20 

3 

15 

53 

5 

Pistole,  1801... 

4 

H 

90*1 

20 

3 

3 

88 

4 

Coronilla,  Gold  Dollar  or 

| 

Yintem,  1801............ ...... 

1 

3 

22*8 

20 

1*1 

— 

98 

3 

77 


*!■ 


To  find  the  Proportion  of  Gold  in  a mixture 
of  Gold  and  Quartz  by  Calculation* 


The  specific  gravity  of  gold  =19.000 
The  specific  gravity  of  quartz  = 2.600 


These  numbers  can  be  corrected  when 
^experiment  shows  the  specific  gravities  to 
be  different. 

A.  Ascertain  the  specific  gravity  of  the 
mixture  of  gold  and  quartz.  Suppose  it  to 
be  8.067. 

B.  Deduct  the  specific  gravity  of  the 


* This  article  is  taken  from  J.  A.  Phillips’s  “Gold 
Mining  and  Assaying/’  (London,  1852,)  p.  85,  a work 
published  since  the  first  edition  of  this  little  volume, 
and  one  which,  like  the  other  productions  of  its  author, 
it  is  needless  more  particularly  to  recommend  to  those 
who  pay  attention  to  the  recent  publications  in  this 
department  of  applied  chemistry. 

7* 


78 


THE  ASSAYER’S  GUIDE. 


mixture  from  the  specific  gravity  of  the 
gold : the  difference  is  the  ratio  of  the 
quartz  by  volume  : — 

19.000  — 8.067  = 10.933 

C.  Deduct  the  specific  gravity  of  the 
quartz  from  the  specific  gravity  of  the  mix- 
ture : the  difference  is  the  ratio  of  the  gold 
by  volume 

8.067  — 2.600  = 5.467 

D.  Add  these  ratios  together,  and  pro- 
ceed by  the  rule  of  proportion.  The  pro- 
duct is  the  per-centage  of  gold  by  bulk  : — - 

10.983  + 5.467  = 16.400 
16.4  is  to  5.467  as  100  is  to  33,35 

E.  Multiply  the  per-centage  of  gold  by 
bulk,  by  its  specific  gravity.  The  product 
is  the  ratio  of  gold  in  the  mixture  by 
weight 

33.35  x 19.00  = 633.65 

F.  Multiply  the  per-centage  of  quartz  by 
bulk,  by  its  specific  gravity.  The  product 


PROPORTIONS  OP  GOLD. 


T9 


is  the  ratio  of  the  quartz  in  the  mixture  by 
weight : — 

66.65  x 2.60  = 173.29 

G.  To  find  the  per-centage  of  gold,  add 
these  ratios  together,  and  proceed  by  the 
rule  of  proportion  : — 

633.65  + 173.29  = 806.94 

806.94  is  to  633.65  as  100  is  to  78.53 

Hence,  a mixture  of  quartz  and  gold, 
having  the  specific  gravity  of  8.067,  con- 
tains 78.53  per  cent,  of  gold  by  weight. 


80 


XII. 

Assay  of  Platinum  Ores . 

This  metal  lias  as  yet  occurred  in  the 
United  States  only  in  gold  ores,  and  even 
then  in  the  merest  traces,  and  hence,  per- 
haps, it  would  barely  deserve  a mention  in 
these  pages ; but  the  great  interest  attached 
to  its  occurrence,  as  so  rare  a metal  all  over 
the  world,  and  its  useful  application  to 
chemical  purposes,  has  caused  me  to  insert 
some  rules  for  its  assay. 

If  the  ore  contain  platinum  in  no  larger 
amount  than  three  or  four  per  cent,  of  the 
gold,  the  former,  as  already  observed  in 
Article  V.  on  quartation,  will  be  entirely 
dissolved  in  the  nitric  acid  used  on  ac- 
count of  the  silver.  From  this  solution  of 
the  two  metals  precipitate  the  silver  with 
common  salt,  or  muriatic  acid,  as  chloride 


ASSAY  OF  PLATINUM  ORES. 


81 


of  silver;  filter  and  wash  until  the  water 
dropping  from  the  funnel  no  longer  con- 
tains any  of  the  platinum  solution.  This 
latter  evaporate  to  dryness,  after  adding 
sal-ammonia.  Wash  it  with  alcohol,  (see 
Gold,  art.  VIII.)  and  heat  the  double  chlo- 
ride of  platinum  and  ammonium  to  red- 
ness, thus  producing  a spongy  mass  of  pure 
platinum. 

If  there  be  more  than  three  or  four  per 
cent,  of  platinum  in  the  gold,  its  presence 
is  readily  perceived,  from  various  circum- 
stances: thus,  in  evaporating  the  lead  a 
higher  temperature  is  necessary  than  is 
commonly  the  case,  to  make  the  metal  flow 
and  acquire  a round  form ; secondly,  the 
bright  light  cannot  be  observed;  thirdly, 
the  surface  of  the  button  is  crystalline  or 
rough,  and  when  large,  flat  and  quite  ir- 
regular, besides  looking  dull  and  having  a 
more  or  less  grayish  colour;  fourthly,  the 
nitric  acid  is  frequently  discoloured;  and 
fifthly,  the  little  roll  of  gold  is  not  of  a 


82 


THE  ASSAYED' S GUIDE. 


pure  gold  yellow,  but  rather  inclining  to- 
wards steel  gray. 

After  having  thus  recognised  a larger 
quantity  of  this  metal,  it  becomes  neces- 
sary, since  copper  is  frequently  present,  to 
make  a prior  test,  to  ascertain,  by  cupella- 
tion,  the  amount  of  the  alloy  of  gold  and 
platinum.  After  that,  two  assays  should 
be  made;  the  one,  to  ascertain  the  exact 
conjoint  per-centage  of  the  two;  the  other, 
inquartation  (pure)  silver  being  added,  to 
discover  the  amount  of  the  gold  alone. 
The  difference  of  the  two  results  gives  the 
amount  of  platinum.  The  inquartation 
silver  should  not  be  more  than  from  two 
and  a half  to  three  times  the  weight  of  the 
alloy  of  gold  and  platinum  ; and  it  is  often 
well  to  add  a certain,  accurately  weighed 
quantity  of  pure  gold  at  the  same  time,  so 
that  the  gold  may  afterward  be  procured 
in  one  connected  sheet  or  piece.  This 
ought  particularly  to  be  done,  when  there 
is  as  much  as  a third  the  weight  of  the 


ASSAY  OF  PLATINUM  ORES. 


83 


gold  in  platinum,  as,  for  instance,  in  the 
platinum  grains  of  the  Ural  Mountains, 
which  contain  about  80  per  cent.  The 
button  is  hammered  flat,  and  proceeded 
with  exactly  as  gold  ores,  the  platinum 
dissolving  with  the  silver  in  nitric  acid. 
But  as  it  does  not  do  so  as  easily  as  the 
latter,  at  least  when  in  large  quantities,  it 
is  necessary  to  repeat  the  process  from  the 
quartering  on  once  or  twice,  using  silver 
and  lead  over  again.  This  should  be  done 
until  nothing  but  the  silver  used  is  dis- 
solved in  the  nitric  acid,  or,  in  other  words, 
until  two  assaj's  following  one  another 
have  produced  the  same  results,  a thing 
that  may  not  occur  until  the  fifth  time. 

It  should  be  remarked,  that  it  is  neces- 
sary to  add  a little  more  lead  for  cupella- 
tion,  than  would  be  done  if  no  platinum 
were  in  the  ore;  and  also,  that  just  before 
the  bright  flash  of  light  occurs  during  the 
operation  of  quartering,  it  is  well  to  shake 
the  cupel  a little,  to  make  the  button 


84 


THE  ASSAYER’S  GUIDE. 


stiffen,  as  soon  as  the  last  lead  has  entered 
the  former,  by  which  the  platinum  will  be 
more  regularly  distributed  in  the  alloy,  and 
cannot  so  well  collect  in  different  uncon- 
nected lumps,  unexposed  afterward  to  the 
action  of  the  acid.  The  platinum  may 
then  be  extracted  and  reduced  from  the 
solution,  as  above. 


85 


XIII. 

Assay  of  Copper  Ores — German  and  Hun- 
garian Method. 

This  ore,  if  a sulphuret,  as  is  very  gene- 
rally the  case,  should,  after  having  been 
reduced  to  the  finest  possible  powder,  be 
submitted  to  the  process  of  roasting,  vul- 
garly termed  calcining.  For  this  purpose 
one  part  by  weight  of  the  ore  is  mixed 
up  with  one  fifth  of  graphite,  (black-lead,) 
which,  consisting  of  carbon  in  a more  con- 
densed state  than  that  element  occurs  in 
charcoal,  is,  therefore,  so  much  the  more 
effectual  in  driving  off  the  sulphur.  This 
mixture  of  the  two  should  be  exposed  to 
an  intense  red-heat  in  the  cupel,  (fig.  1,) 
(painted  over  on  the  inside  with  red  chalk, 
or  Spanish  red,  to  prevent  adhesion,)  for 

about  twenty  minutes,  after  which  it  is 

8 


86 


THE  ASSAYER’S  GUIDE. 


to  be  taken  out,  and  stirred  up  with  a small 
iron  ladle  to  expose  the  unburnt  parts  of 
graphite,  when  it  should  again  be  exposed 
in  the  muffle.  In  about  a quarter  of  an 
hour  we  take  it  out  again,  pound  it  over, 
for  the  mass  is  generally  clogged,  and  mix 
it  with  about  twice  its  weight  of  charcoal- 
dust,  after  which  we  continue  the  roasting 
for  about  one-half  to  a full  hour,  according 
as  the  ore  contains  a little  or  much  sul- 
phur, vapours  of  which  may  be  seen  rising 
during  the  whole  of  this  process. 

After  this  the  ore  has  a reddish,  or  what 
is  generally  called  a ferruginous  colour, 
and  we  now  take  it  from  the  first,  crucible, 
and  introduce  it  into  that  represented  in 
fig.  4,  Plate  II.,  or  if  not  in  possession  of 
such,  into  a Hessian  crucible,  fig.  5,  on  the 
same  plate.  For  this  purpose,  however, 
some  black  flux  should  be  provided.  It 
consists  of  carbonate  of  potash  and  lime, 
and  is  made  by  igniting  together  one  part 
by  weight  of  saltpetre,  and  two  of  com- 


ASSAY  OF  COPPER  ORES. 


87 


mon  tartar.  The  flux  produced  should  be 
kept  carefully  corked  to  prevent  the  ab- 
sorption of  hygroscopic  water.  It  is  still 
better  to  make  it  only  when  required  for 
immediate  use. 

If  the  ore  is  poor,  one  tenth  part  by 
weight  of  oxide  of  antimony,  (antimonious 
acid,)  or  of  arsenic,  (arsenious  acid,)  or  if  it 
is  richer,  fifteen  per-cent,  of  pure  lead*  are 
requisite,  as  will  hereafter  be  seen  to  make 
the  particles  of  copper  unite.  One  of  these 
'together  with  three  parts  of  black  flux,  one 
half  the  weight  in  borax,  and  two  parts  of 
table  salt,  must  then  be  added  to  the  roast- 
ed ore,  though  none  except  a part  of  the 

* Some  assayers  use  neither  of  these  three,  on  the 
ground  that  the  arsenic,  as  occasionally  even  40  per- 
cent. may  be  taken,  is  very  difficult  to  separate  from 
the  copper,  and  that  the  antimony  may  unite  with  part 
of  the  same,  forming  an  antimoniate.  They  therefore 
only  employ  borax  and  black  flux,  in  about  the  same 
proportions,  however,  as  given  above.  It  is  hard  to 
say  which  is  best,  and  it  must  be  left  to  the  discretion 
and  experience  of  the  assayer  to  act  as  may  be  most 
suitable  to  his  peculiar  ores. 


88 


THE  ASSAYEIl’S  GUIDE. 


flux  are  mixed  with  the  mineral  now  in- 
vestigating. The  salt  is  merely  used  to 
form  a crust  over  the  whole.  When  all 
have  thus  been  placed  in  the  crucible,  they 
are  covered  over  with  a piece  of  charcoal, 
cut  to  match  the  size  of  the  vessel ; after 
which  the  cover  is  put  on.  We  then  ex- 
pose it  to  a white-heat  for  about  one-half 
to  one  full  hour,  as  may  be  most  conve- 
nient, either  in  the  draught  furnace,  fig.  6, 
Plate  I.,  or  in  the  muffle  furnace;  in  which 
latter  case,  we  must  allow  the  longest 
period  of  time. 

The  carbon  of  the  flux  is  intended  to 
reduce  the  peroxide  of  copper  produced  by 
roasting,  while  its  carbonate  of  potash 
unites  with  the  earthy  contents  of  the  ore 
and  the  oxides  of  other  metals  present, 
such  as  iron,  which  would  otherwise  also  be 
reduced  to  their  metallic  state.  With  these 
it  forms  a slag,  the  borax  being  added  to 
make  it  flow  easy,  and  allow  the  copper  to 
collect  in  one  button. 


ASSAY  OF  COPPER  ORES. 


89 


On  cooling,  we  break  open  the  crucible, 
and,  on  removing  the  slag,  extract  a spheri- 
cal piece  of'  impure  or  alloyed  copper, 
according  as  other  metals  may  chance  to 
occur  in  the  ore.  If  any  intermediate 
crust  should  have  formed  between  the 
button  and  the  slag,  the  ore  was  not  proper- 
ly roasted,  a part  of  the  copper  not  reduced, 
and  consequently  the  assay  is  worthless. 

In  a good  assay  the  slag  should  be  black 
and  vitreous  in  appearance,  never  of  an 
'earthy  texture.  If  striated  or  speckled 
with  red,  we  may  know  that  protoxide  of 
copper  is  dissolved  in  it,  and  again  that  the 
whole  cannot  be  productive  of  an  accurate 
result.  Much  attention  is  required  during 
this  test,  and,  as  already  mentioned  under 
the  heads  of  silver  and  gold,  the  final  result 
depends  entirely  upon  the  care  taken  by 
the  assayer.  If  well  managed,  however,  as 
here  directed,  he  can  hardly  fail  to  be  suc- 
cessful. 

The  button,  as  remarked  above,  may 

8* 


90 


THE  ASSAYER’S  GUIDE. 


vary  in  purity.  It  generally  contains  some 
iron,  and  (since  these  metals  frequently 
exist  in  copper  ores)  lead,  bismuth,  tin, 
cobalt,  nickel,  antimony,  and  arsenic — the 
latter  two  in  particular,  if  they  were  added 
in  the  process  of  reduction.  Thus  it  very 
rarely,  if  ever,  happens,  that  a copper  ore 
is  sufficiently  pure  to  require  no  third 
process.  The  less  admixtures  the  alloy  con- 
tains, the  less  brittle  and  the  more  ductile  it 
is.  Nickel  particularly  tends  to  harden  it. 

To  remove  the  foreign  metals,  the  button 
is  put  in  a piece  of  paper,  with  sufficient 
borax  to  cover  it,  (one-fourth  to  one-third 
part  by  weight,  rather  more  than  less,)  and 
if  no  lead  occur  in  the  ore,  with  about  from 
five  to  ten  per-cent,  of  that  metal,  which 
amount,  however,  should  increase  up  to 
forty,  or  even  more,  if  there  are  many 
impurities  in  the  alloy.  Even  if  this  be 
not  the  case,  it  is  always  safer,  and  can 
never  produce  any  bad  effect,  to  add  much. 

A crucible  of  the  kind  illustrated  in  fig.  3, 


ASSAY  OF  COPPER  ORES. 


91 


Plate  II.,  should  be  brought  to  a bright 
white-heat  in  the  muffle.  Coals  may  be 
placed  round  to  increase  the  temperature, 
which  should  be  so  great,  that  the  copper, 
on  being  introduced,  trapped  in  paper  with 
borax  and  lead,  may  melt  in  a few  minutes. 

As  long  as  the  tongs  held  over  the  button 
are  reflected,  or  rainbow  colours  are  yet 
seen  to  flicker  over  its  surface,  lead  is  still 
present.  As  with  silver  and  gold,  too  great 
heat  ought  not  to  be  employed.  When  the 
lead  has  left,  we  immediately  take  out  the 
crucible,  and  immerse  it  in  water,  to  pre- 
vent any  copper  from  oxidating  unneces- 
sarily. The  button  of  pure  copper  is  then 
broken  out  and  weighed.  A slight  loss  can- 
not be  prevented,  as  it  is  impossible  to  pre- 
vent some  oxide  of  copper  from  being  formed, 
and  we  must  therefore  grant  a larger  per- 
centage than  the  assay  would  direct. 

At  least  two  assays  should  be  made  at 
once,  to  compare  the  results,  and  take  the 
average. 


92 


XIV. 

Assay  of  Copper  Ores — English  Method . 

At  the  copper  mines  in  Cornwall,  a mode 
of  assaying  is  employed,  which  in  several 
of  its  minutiae  differs  considerably  from  the 
one  just  described.  It  should  be  remarked 
that  this  method  is,  properly  speaking,  only 
applicable  to  sulphurets,  as  all  copper  con- 
tained in  the  ore  as  a pure  oxide,  or  com- 
bined with  an  acid,  will  pass  over  into  the 
slag  during  the  reduction  process ; and  that 
therefore  if  these  latter  are  present,  some 
means  should  be  employed,  as  shall  be 
shown  hereafter,  to  extract  them  from  the 
slags,  when  the  other  parts  of  the  assay  are 
concluded. 

The  ore,  being  a sulphuret,  should  be 
roasted  as  directed  in  the  foregoing  Ger- 
man or  Hungarian  method,  after  which  it 


ASSAY  OF  COPPER  ORES. 


93 


is  mixed  with  from  one  to  one  and  a half 
parts  of  pounded  glass,  which  should,  how- 
ever, contain  no  lead  or  arsenic,  from 

twenty-five  to  fifty  per-cent,  of  saltpetre, 

/ 

and  fifty  per-cent,  of  borax.  Together  with 
these,  it  is  exposed  to  a strong  melting  heat 
in  a clay  crucible.  On  cooling,  the  button 
is  removed,  as  is  the  case  in  the  other  mode 
of  procedure,  more  common  on  the  conti- 
nent of  Europe. 

Having  thus  reduced  the  copper,  it  is  ne- 
cessary to  purify  it,  as  was  also  done  in  the 
other  assay.  I must  observe,  however, 
that  this  part  of  the  Cornwall  process, 
again,  can  only  be  applied  where  very 
little  lead  is  contained  in  the  copper  ore. 

For  this  purpose,  some  white  flux  should 
be  prepared,  which  is  done  by  igniting  to- 
gether equal  parts  of  saltpetre  and  tartar. 
Being  as  susceptible  to  the  effects  of  atmo- 
spheric moisture  as  black  flux,  it  requires 
the  same  precaution  as  regards  its  preser- 
vation. 


94 


THE  ASSAYER’S  GUIDE. 


The  button  of  copper  alloy  is  then  ham- 
mered out  flat,  to  a sheet  as  thin  as  it  will 
allow  of,  without  breaking.  It  is  then  ex- 
posed in  a crucible,  (fig.  3,)  already  red- 
hot,  and,  as  soon  as  it  melts,  covered  with 
white  flux.  Some  table-salt,  from  which 
the  water  of  crystallization  has  been  re- 
moved by  heat,  is  frequently  added  to  give 
a covering  and  protect  the  copper  from  too 
immediate  contact  with  the  atmosphere, 
which,  together  with  the  heat,  would  un- 
avoidably create  a free  oxidation.  A con- 
siderable ebullition  is  produced,  on  the  sub- 
siding of  which,  and  when  therefore  the 
mass  flows  quietly,  the  contents  of  the  cru- 
cible are  poured  into  an  iron  mould,  (fig.  6, 
Plate  II.,)  greased  over  beforehand,  from 
which  the  mass  should  be  removed  with  a 
pair  of  tongs,  as  soon  as  sufficiently  consoli- 
dated, to  be  dipped  in  water,  which  ena- 
bles us  to  separate  the  slag  from  the  copper 
with  greater  ease.  The  purity  of  the  latter 
is  known  by  its  malleability,  and  by  its 


ASSAY  OF  COPPER  ORES. 


95 


not  cracking  much  at  the  margin,  when 
stretched  on  the  anvil  under  the  blows  of  a 
hammer.  Should  this  test  prove  its  yet 
uncleansed  state,  it  ought  again  to  be  sub- 
mitted to  the  operation  just  concluded. 
Sometimes  it  is  necessary  to  repeat  this 
several  times. 

It  has  already  been  mentioned,  that,  par- 
ticularly when  not  all  the  copper  in  an 
ore  is  contained  in  the  shape  of  a sulphu- 
ret,  it  is  impossible  to  prevent  some  of  this 
metal  from  escaping  into  the  slag;  and 
therefore,  to  diminish  this  loss  as  much  as 
possible,  English  assayers  collect  the  slags, 
both  of  the  reducing  and  of  the  purifying 
processes,  and,  pounding  them  up  together, 
mix  them  with  an  equal  quantity  of  tartar 
and  some  powdered  coke. 

This  mixture  is  then  melted  in  a Hessian 
crucible,  after  being  covered  over  with  com- 
mon salt.  The  little  button  produced  in 
this  way  is  of  course  impure,  and  requires 
the  same  treatment  as  the  larger  one,  origi 


96 


THE  ASSAYER’S  GUIDE. 


ii ally  procured.  This  second  button  is 
weighed  together  with  the  large  one,  and 
the  result  will  give  very  accurately  the 
per-centage  of  copper  in  the  ore. 


9T 


XV. 

Assay  of  Lead  Ores  by  Heat . 

There  is  no  way  of  assaying  lead  ores  by 
heat  which  gives  the  full  amount  of  the 
metal,  as  it  is  so  easily  oxidized  by  a high 
temperature.  Generally,  the  loss  varies 
from  one-sixth  to  one-twelfth,  or  yet  more 
commonly  is  about  a tenth;  and  for  this 
reason,  the  result  of  the  assay  should  after- 
ward be  increased  by  A,  on  giving  the  per- 
centage of  lead. 

The  assay  is  performed  in  the  crucible, 
fig.  4,  or  in  the  Hessian  one.  The  part  of 
ore  used  ought  to  be  about  two  hundred 
grains,  as  lead  ores  (galena,  a sulphuret  of 
lead  is  the  most  common)  are  very  heavy, 
and  therefore  are  comparatively  small  in 
bulk.  Three  parts,  or  here  six  hundred 
grains,  of  black  flux  are  mixed  up  with  the 

9 


98 


THE  ASSAYER’S  GUIDE. 


powdered  ore. 

A little  piece  of  very  thick  wire,  or  of  a 
round  iron  bar,  weighing  from  thirty  to 
forty  per-cent,  of  the  weight  of  the  lead 
ore,  is  placed  on  the  top,  in  the  crucible. 

We  then  expose  the  whole  to  a strong, 
steady  red-heat,  for  about  an  hour,  in  the 
bellows  furnace,  fig.  6,  Plate  I.  This  is  ef- 
fected by  first  placing  the  crucible  on  the 
brick,  and  then  making  a layer  of  cold 
burnt  coals,  as  high  as  the  brick.  On  this 
come  the  live  coals,  and  on  them  the  un- 
burnt ones  up  to  the  top  of  the  furnace. 
When  burnt  down,  we  take  out  the  cruci- 
bles, and  thus  obtain  a button  of  pure  lead 
and  some  slag,  besides  a remaining  portion 
of  the  iron. 

The  latter  should  be  added  in  excess,  to 
insure  the  entire  absorption  of  the  sulphur. 
Galena  contains,  in  hundred  parts,  13.45 
parts  of  sulphur  to  86.55  of  lead,  which 
Would  require  22.67  parts  of  metallic  iron 
to  form  sulphuret  of  iron,  consisting  of  37.23 


ASSAY  OF  LEAD  ORES  BY  HEAT. 


99 


parts  of  sulphur  to  62.77  of  iron.  If,  there- 
fore, two  hundred  grains  of  the  ore  are 
used,  the  iron  should  weigh  from  60  to  100 
grains.  Filings  ought  never  to  be  used,  as 
they  are  always  covered,  to  a smaller  or 
greater  amount,  with  oxide.  Besides,  it  is 
very  difficult  to  get  them  as  free  from  im- 
purities as  wire.  Weighed  pieces  of  the 
latter  should  be  kept  in  some  vial  or  box 
for  this  purpose. 


100 


XVI. 

Assay  of  Lead  Ores  by  a Wef  Process. 

This  method  will  be  found  much  the 
more  accurate  of  the  two,  although  it  may 
not  often  happen  that  a practical  assayer 
has  sufficient  time  for  this  proceeding.  (See 
Woehler’s  Anal.  Chem.) 

The  ore  (galena)  should  be  powdered 
much  finer  even  than  in  the  assay  by  heat, 
after  which  it  is  moistened  with  fuming 
nitric  acid,  and  digested  in  the  sand-bath, 
by  which  process  it  is  entirely  changed 
from  the  sulphuret  to  the  sulphate  of  lead. 

If  the  mass  be  diluted  with  water  and 
filtered,  the  merest  traces  only  of  lead  can 
be  found  in  the  solution,— quantities  too 
small  to  deserve  any  farther  attention.  If 
the  ore  contain  copper,  iron,  or  silver,  they 
will  be  contained  in  this  filtered  solution ; 


ASSAY  OF  LEAD  ORES  BY  A WET  PROCESS.  101 

the  first  are  then  discovered  by  ammonia, 
the  latter  by  muriatic  acid. 

Should  fuming  nitric  acid  not  be  at 
hand,  and  if  therefore  a weaker  kind  is 
used,  a mixture  of  sulphate  of  lead  and  sul- 
phur is  produced,  together  with  a solution 
of  nitrate  of  lead.  From  this  latter  the 
metal  should  be  precipitated  with  sulphuric 
acid.  By  heating  the  dried  residue, — after 
filtering  and  washing,  by  pouring  water 
qver  it  while  yet  on  the  filter, — sulphur  is 
evaporated  and  sulphate  of  lead  is  retained. 

In  both  cases,  the  lead  produced  is  a 
sulphate,  and  in  this  shape  it  should  be 
weighed,  and  from  the  result  the  amount 
of  the  former  alone  may  be  easily  calcu- 
lated, as  will  be  seen  from  the  sequel. 

Sulphate  of  lead  consists,  in  100  parts  by 
weight,  of 

Oxide  of  lead  . 73.56 
Sulphuric  acid  . 26.44 


9* 


100.00 


102  THE  ASSAYER’S  GUIDE. 

and  the  oxide  of  lead,  again,  of 

Lead  .....  92.83 
Oxygen  ....  7.17 

Hence  we  say,  if  100  parts  of  oxide  of  lead 
contain  92.83  of  pure  lead,  then  73.56  of 
pure  lead  contain  68.285748  parts;  or,  in 
other  words,  sulphate  of  lead  consists  ot 

Lead  . . . 68.285748 
Oxygen  . . . 5.274252 

Sulphuric  acid  . 26.440000 

100.000000 

For  this  assay  about  twenty  grains  only 
need  be  taken.  A smaller  amount  might 
make  us  incapable  of  finding  the  real  quan- 
tity of  lead,  while  a larger  one  would  only 
give  us  unnecessary  trouble. 


103 


XVII. 

Assay  of  Iron  Ores  by  Heat . 

One  part  of  the  ore,  about  a hundred 
grains,  thoroughly  pulverized,  is  mixed  with 
from  thirty  to  a hundred  grains  of  calcined 
borax.  The  quantity  of  the  latter  varies 
according  to  the  purity  of  the  mineral,  and 
increases  when  it  contains  many  foreign 
admixtures. 

If  the  ore  contains  Sulphur,  it  ought  first 
to  be  roasted,  as  was  the  case  with  the 
assays  of  other  metals  already  described. 

A Hessian  crucible  is  then  prepared  with 
coal,  as  already  directed  in  the  description 
of  those  vessels  under  the  head  of  Utensils 
and  Implements.  Into  the  hollow  in  the 
centre,  the  mixture  of  ore  and  borax  is 
poured,  and  on  that  some  charcoal  powder; 
after  which  the  cavity  is  entirely  covered 


104 


THE  ASSAYER’S  GUIDE. 


with  a piece  of  charcoal.  The  crucible  is 
then  closed,  the  number  of  the  assay  being 
marked  on  the  inner  surface  of  the  cover. 
This  is  then  fastened  down  air-tight  with 
some  putty. 

The  iron  ore,  after  these  preliminary 
arrangements,  is  to  be  submitted  to  a reduc- 
tion process  in  the  furnace,  fig.  6,  Plate  I., 
which  lasts  about  three-quarters  of  an 
hour. 

At  the  extensive  iron-works  on  the  Hartz 
Mountains  in  the  interior  of  Germany,  a 
very  simple  apparatus  is  used  instead  of 
the  other  furnace,  of  which,  on  account  of 
its  portability,  I here  give  a description. 
It  consists  simply  of  an  open  cast-iron  pot 
or  jar,  measuring  about  a foot  across,  and 
one  and  a half  in  height,  and  having  a 
plate  of  sheet-iron,  perforated  with  many 
little  holes  an  inch  in  diameter,  instead  of 
a grate.  This  leaves  a vacant  space  of 
about  two  inches  below,  to  receive  the 
ashes.  The  latter  partition  has  two  open- 


ASSAY  OF  IRON  ORES  BY  HEAT. 


1G5 


ings ; one,  the  door  to  take  out  these  cin- 
ders— the  other,  to  introduce  the  end  of  the 
bellows.  Above  the  iron  plate,  on  which 
r the  crucibles  are  directly  placed,  without 
any  brick,  a coating  of  fire-clay,  an  inch 
thick,  extends  to  the  mouth  of  the  jar. 

The  latter  is  furthermore  supplied  with 
three  or  four  short  legs,  and  a handle  on 
each  side. 

In  this  furnace  the  process  lasts  about 
an  hour  and  a quarter. 

In  both  cases,  the  button  produced  con- 
tains exactly  the  same  impurities,  carbon, 
earths,  acids,  or  other  metals,  as  pig-iron 
would,  if  procured  from  the  same  ore,  and 
therefore  this  assay  is  only  to  be  used  for 
furnaces.  For  these  it  entirely  suffices; 
but  to  ascertain  the  true  amount  of  pure 
iron,  the  wet  analysis  should  be  resorted  to, 
the  same  as  with  other  ores ; and  it  is  for 
this  that  I shall  give  directions  in  the  next 
chapter  how  to  discover  or  calculate  the 
real  per-centage  of  the  pure  metal,  or  to 


106 


THE  ASSAYER’S  GUIDE. 


assay  the  pig-iron  produced  in  the  process 
by  heat. 

It  may  not  be  uninteresting  to  many, 
who  may  honour  these  pages  with  their 
perusal,  to  become  acquainted  with  a me- 
thod for  obtaining  chemically  pure  iron, 
as  given  by  Karsten  in  his  famous  and 
voluminous  works  on  this  metal.  It  is 
described  in  vol.  i.,  pages  167,  168.  He 
says,  to  procure  chemically  pure  iron,  take 
the  best  bar-iron  of  commerce,  e.  g.  Swedish 
iron  in  the  shape  of  small  wire ; cut  it  up 
in  short  pieces,  and  then  mixing  it  with 
about  a fourth  part  by  weight  of  oxide  of 
the  same  metal,  melt  it  in  a Hessian  cru- 
cible. To  cover  it,  use  a compound  flux, 
consisting  of  pure  quartz,  pure  lime,  and 
equally  pure  carbonate  of  potash,  in  pro- 
portions capable  of  furnishing  a glass  or 
slag,  not  flowing  too  easily,  but  of  rather  a 
tough  consistency. 

For  the  manufacture  of  an  oxide  of  iron, 
free  from  all  admixtures  of  foreign  metals, 


ASSAY  OF  IKON  ORES  BY  HEAT. 


107 


it  is  best  to  use  small  clean  wire,  oxidizing 
it  by  vapours  of  water. 

The  button  thus  produced  has  a re- 
markably white  colour,  a strong  metallic 
lustre,  and  is  more  ductile  than  the  best 
varieties  of  soft  bar-iron.  Particularly  cha- 
racteristic, however,  is  its  great  specific 
gravity,  amounting  to  7.9654,  while  that 
of  wrought-iron  is  7.6  to  7.9,  and  of  cast- 
iron  only  from  7.0  to  7.5.  The  only  im- 
purity this  metal  may  be  discovered  to 
possess  occurs  as  slight  traces  of  silicium, 
and  therefore  it  may  be  considered  to  be  as 
pure  as  it  possibly  can  be  made,  even  by  a 
process  conducted  only  upon  the  rules  and 
principles  of  wet  analysis,  and  thus  in  this 
shape  it  is  utterly  unknown  to  the  mere 
practical  metallurgist  or  smelter. 


108 


XVIII. 

Fvdiss  Process  for  Iron  Ores  and  Iron. 

This  method,  though  remarkable  for  its 
simplicity,  is  a very  sure  one,  not  only  to 
ascertain  the  quantity  of  iron  in  an  ore,  but 
to  acquaint  us  with  the  peculiar  degree  of 
oxidation  in  which  it  exists,  and  also  the 
amount  of  each  oxide,  which  it  is  often  not 
only  very  interesting,  but  useful  to  know. 
Many  ores,  particularly  the  magnetic  ones, 
contain  both  the  peroxide  and  the  prot- 
oxide, and  the  only  ones  to  which  this 
process  cannot  be  applied  are  those  con- 
taining arsenious  acid,  not  a very  common 
ingredient. 

The  process  discovered  or  invented  by 
Fuchs  is  founded  on  the  fact,  that  chemically 
pure  muriatic  acid,  when  atmospheric  air  is 
excluded,  is  incapable  of  dissolving  any 


FUCHS’S  PROCESS  FOR  IRON  ORES.  109 

copper;  but  that,  when  peroxide  of  iron  is 
contained  in  it,  a corresponding  quantity  of 
Jhat  metal  becomes  soluble,  a muriate  or 
chloride  of  iron  and  chloride  of  copper  being 
thus  formed. 

The  ore  is  dissolved  in  muriatic  acid,  and, 
if  necessary,  filtered.  A small  round-bot- 
tomed vial  should  be  used.  Into  the  solu- 
tion a clean  weighed  strip  of  copper  is 
placed,  and  the  vessel  corked,  and  covered 
with  a piece  of  bladder,  tied  down  round 
the  neck  until  we  are  ready  to  boil  it. 
This  is  best  done  in  a water-bath,  and 
should  last  until  no  more  copper  is  received 
by  the  acid.  The  former  is  then  taken  out, 
well  washed  in  water,  dried  with  a towel, 
and  immediately  weighed. 

The  difference  in  the  weight  of  the 

copper  is  all  that  is  required  to  ascertain 

the  amount  of  peroxide  of  iron  in  the  ore, 

for  we  need  only  multiply  this  by  the 

equivalent  of  peroxide  of  iron,  which  Fuchs 

takes  to  be  10,  and  divide  the  product  by 
10 


no  THE  ASSAYER’S  GUIDE. 

31.7,  the  equivalent  of  copper.  The  quo- 
tient gives  the  quantity  of  peroxide  con- 
tained in  the  solution  or  ore. 

To  know  the  whole  amount  of  iron  in  it, 
we  need  only  weigh  off  another  part,  (10 — 
15  grs.,)  dissolve  it  in  muriatic  acid,  and 
then  digest  with  chlorate  of  potash,  to 
transform  the  protoxide  into  peroxide,  after 
which,  copper  will  decompose  the  whole. 
Instead  of  40,  the  equivalent  of  peroxide 
of  iron,  we  insert  28,  the  equivalent  of  the 
pure  metal,  into  our  calculations.  By  sub- 
tracting the  amount  of  the  peroxide  from 
the  last  result,  the  amount  of  the  protoxide 
is  found. 

The  presence  of  alumina,  silica,  &c.  has 
no  effect  on  this  assay,  though  the  existence 
of  copper  in  it  would  represent  the  ore  as 
poorer  than  it  really  is.  The  latter,  how- 
ever, rarely  occurs  in  common  iron  or  its 
ores  except  in  mere  traces,  and,  as  such,  it 
produces  no  material  difference. 


Ill 


XJX. 

Assay  of  Quicksilver  Ores . 

This  metal  is  one  of  those  which  some- 
times occur  in  the  virgin  state,  though  by 
far  the  most  common  shape  in  which  it 
presents  itself  is  the  bisulphuret,  commonly 
termed  cinnabar,  which  in  its  perfectly 
pure  state  consists  of : — 

Mercury  ....  86.287 
Sulphur  ....  13.713 

100.000 

Its  formula  being  Hg  S.  A specimen  from 
Japan,  analyzed  by  Klaprcth,  gave: — 
Mercury  ....  84.50 

Sulphur  . . . . 14.75 

99.25 

Which,  though  it  must  have  contained 


112 


THE  ASSAYER’S  GUIDE. 


0.75  of  other  ingredients  not  mentioned 
in  the  analysis,  shows  that  it  possessed 
as  much  as,  according  to  the  above-calcu- 
lated composition,  it  could  be  expected  to 
contain. 

It  is  not  the  place  here  to  give  the 
analyses  of  other  casual  occurrences  of 
this  metal,  such  as  perhaps  are  only  to  be 
found  in  the  cabinet  of  the  mineralogist; 
and  I shall  therefore  proceed  to  describe 
the  manner  in  which  the  assays  of  mercurial 
ores  are  performed. 

In  all  cases  the  mercury  is  procured  by 
simple  distillation,  for  which  purpose,  where 
not  originally  uncombined,  it  is  necessary 
first  to  disengage  it. 

In  distilling  quicksilver,  an  iron  retort 
covered  outside  with  a coating  of  clay  is 
commonly  used.  The  neck  should  be  so 
contrived  that  it  can  be  unscrewed,  to 
facilitate  cleaning  the  interior.  Ketorts  or 
tubes  of  clay,  glazed  externally,  are  also 
applicable,  and  are  preferred  by  some;  but 


ASSAY  OF  QUICKSILVER  ORES. 


113 


those  of  iron  are  safer,  inasmuch  as  the 
vapors  of  mercury  cannot  possibly  pene- 
trate and  escape  through  them. 

To  produce  the  necessary  heat,  which 
should  not  exceed  a mild  red,  any  conve- 
nient furnace,  such  as  the  one  described  on 
page  104,  will  answer. 

Any  tumbler  or  beaker-glass  containing 
cold  water  may  be  employed  as  a condenser. 
It  must,  however,  be  remarked  here  that 
the  mouth  of  the  retort  ought  not  to  be 
inserted  into  the  water,  because  in  that  case, 
on  cooling,  the  water  would  rise  up  into  it. 
To  avoid  this,  and  yet  to  prevent  the  escape 
of  the  mercurial  vapors,  a wet  wrapper  of 
paper  or  linen  is  bound  round  the  neck  of 
the  retort,  protruding  sufficiently  to  permit 
of  the  other  end  being  completely  immersed 
in  the  water.  Some  assayers  employ  a little 
bag  tightly  attached  to  the  retort. 

The  fluxes  used  are  various,  and,  accord- 
ing to  their  efficiency,  may  be  enumerated 

thus,  the  first  being  the  best :■ — 

10* 


114 


THE  ASSAYER’S  GUIDE. 


Black  flux,  from  one-half  to  full  weight  of  ore. 
Carbonate  of  soda  or  of  potash,  one-half  u u 
Iron  filings,  from  a quarter  to  a half  u u 

Carbonate  of  lime,  one-half  to  full  u u 

With  charcoal  powder,  one-tenth  to  one-eighth  “ 

The  black  flux  produces  with  cinnabar, 
besides  liberating  the  mercury,  sulphuret  of 
potassium,  while  sulphates  of  soda  and  of 
potash  are  formed  from  the  carbonates. 
The  iron  filings  simply  cause  the  formation 
of  protosulphuret  of  iron,  while  the  quick- 
silver is  disengaged.  The  alkaline  fluxes 
are  chiefly  used  with  the  iron  retorts.  If 
the  quicksilver  is  known  to  exist  only  in 
its  virgin  uncombined  state,  no  flux  is  re- 
quired, and  we  may  immediately  proceed 
to  distil  it  over. 

It  has  been  remarked  above  that  the  heat 
employed  during  the  assay  should  not 
exceed  a moderate  red.  This  point  is  of 
great  consequence  with  cinnabar,  because 
this  sulphuret  is  capable  of  being  sublimated 
in  its  undecomposed  state,  if  the  heat  is  in- 
creased beyond  that  temperature.  If  the 


ASSAY  OF  QUICKSILVER  ORES. 


115 


ore*  contain  chloride  or  bromide  of  mercury, 
these,  too,  will  pass  over ; and,  to  avoid  this, 
the  ore,  if  their  presence  is  suspected,  must 
first  be  mixed  with  soda.  To  render  the 
mixing  more  intimate,  a little  water  is  em- 
ployed, which  must,  however,  be  removed 
before  placing  the  ore  in  the  retort.  It  is 
also  advisable  to  apply  the  heat  gradually, 
and,  when  retorts  are  used,  to  be  particular 
that  they  are  everywhere  heated  equally, 
as  otherwise  quicksilver  might  be  condensed 
in  the  interior  of  the  retort.  When  it  has 
been  ascertained  that  drops  of  quicksilver 
are  no  longer  leaving  the  retort  or  tube, 
and  therefore  that  the  process  is  about  being 
completed,  it  is  advisable  to  fire  up  a little 
before  removing  the  receiving  vessel,  so  that 
particles  of  the  metal  condensed  in  the  neck 
of  the  retort  or  in  the  tube  may  be  forced  out, 
though,  to  insure  this  still  more,  it  is  neces- 
sary to  brush  out  the  neck  of  the  vessel 
with  a little  brush  or  feather. 

The  quicksilver  which  has  collected  in 


116 


THE  ASSAYER’S  GUIDE. 


the  condensing  vessel  is  frequently  indis- 
posed to  join  and  form  a connected  mass; 
but  this  is  easily  brought  about  by  boiling 
it  in  water.  Adhering  moisture  remaining 
when  the  water  is  decanted  should  be  re- 
moved with  blotting-paper. 

From  one-half  to  three  pounds  of  the  ore 
are  commonly  employed  for  the  assay,  de- 
creasing in  quantity  as  the  value  of  the  ore 
increases. 

Perfect  accuracy  can  never  be  attained 
in  the  assay  of  quicksilver  ores  by  heat, 
neither  as  regards  the  perfect  chemical 
purity  nor  the  full  amount  of  the  metal  pro- 
duced; but,  as  the  loss  and  impurity  are  yet 
greater  with  quicksilver  produced  on  a 
large  scale,  this  method  of  treating  the  ore 
will  be  sufficient  for  technical  purposes. 

Berthier,  in  the  Annales  des  Mines,  iv. 
serie,  t.  iii.  p.  820,  suggests  that  when  the 
ore  is  a very  poor  one,  and  when  therefore 
the  large  amount  it  would  be  necessary  to 
use  might  be  the  cause  of  considerable  in- 


ASSAY  OF  Ql'  CKSILVER  ORES. 


117 


convenience  in  the  assay,  the  following  pre- 
paratory process  be  resorted  to.  The  ore 
should  be  digested  with  aqua  regia,  the 
supernatant  liquid  decanted  or  filtered  off, 
the  residue  thoroughly  washed  with  water, 
and  the  acid  solution,  together  with  the 
washings,  evaporated  to  dryness.  All  the 
quicksilver  in  the  shape  of  chloride  is  then 
contained  in  the  last-dried  residue,  and  can 
be  further  treated  in  the  dry  way,  only 
that,  as  above  remarked,  it  is  always  neces- 
sary carefully  to  mix  with  soda,  when 
choride  of  quicksilver  is  present. 

Before  closing  this  chapter  it  will  be  well 
to  describe  the  treatment  necessary  when  a 
quicksilver  ore  contains  arsenic.  I shall 
literally  translate  the  remarks  of  Bodeman 
in  the  work  quoted  in  the  preface.  He 
says : — 

“An  ore  from  Huanca-V61ica,  in  Peru, 
containing  arsenic  (red  sulphuret  of  arsenic, 
&c.)  and  cinnabar,  having  been  submitted 
to  Berthier’s  inspection,  he,  after  various 


118 


THE  ASSAYER’S  GUIDE. 


useless  experiments,  discovered  the  follow- 
ing process  to  be  the  most  adequate  for 
determining  the  mercury  in  it. 

“ The  ore  is  mixed  with  four  or  five  times 
its  weight  of  litharge,  and  then  heated  in  a 
retort.  A flowing,  slag-like  mass  is  formed 
by  the  litharge,  sulphuret  of  arsenic,  &c., 
while  the  cinnabar  is  decomposed  into  sul- 
phurous acid  and  metallic  mercury.  The 
quicksilver  is  completely  volatilized  by  a 
moderate  heat,  and  collected  in  the  condens- 
ing apparatus  and  the  farther  portion  of  the 
neck  of  the  retort.  The  only  precaution 
necessary  during  the  operation  consists  in 
gradually  and  but  moderately  heating  the 
clay  or  glass  retort,  to  prevent  its  being 
perforated  by  the  effects  of  the  litharge  be- 
fore the  process  is  concluded.” 


XX. 


Assay  of  Sulphurets  in  Ores . 

It  is  often  very  necessary  to  know  the 
quantity  of  sulphurets  contained  in  ores,  to 
be  able  to  arrange  accordingly  the  processes 
of  smelting  them. 

To  one  part  of  ore,  50  to  100  grains,  one 
part  of  powdered  glass  and  two  of  borax 
are  required. 

The  borax  is  first  mixed  with  the  ore, 
and  when  placed  in  the  Hessian  crucible, 
or  in  the  lead  and  copper  one,  fig.  4,  Plate 
II.,  both  are  covered  with  the  glass.  The 
crucible  is  then  exposed  to  a bright  red-heat, 
as  with  copper  and  lead,  and  on  cooling  the 
button  is  broken  out,  which  may  contain  in 
the  shape  of  sulphurets,  copper,  lead,  iron, 


120 


THE  ASSAILS  GUIDE. 


&c.,  according  as  these  exist  in  the  ore,  and 
it  may  then  be  examined  for  these  metals 
by  the  means  already  given  in  their  respect- 
ive assays. 


121 


x;xi. 


Mode  of  testing  the  Calorific  Power  of  Coat 
and  other  Fuels* 

It  must  not  be  supposed  that  the  amount 
of  heat  which  a fuel  is  capable  of  producing 
is  entirely  dependent  on  its  chemical  com- 
position. 

Different  means  have  been  adopted  to 
determine  the  efficacy  of  coal  as  a fuel. 
Thus,  Despretz  has  made  experiments  of 
this  kind  by  discovering  the  amount  of 
water  which  a certain  quantity  of  coal  will 
elevate  in  temperature  one  degree  of  the 
centigrade  thermometer.  The  varying  tem- 
perature of  the  water,  however,  must  ever 
prevent  an  accurate  result.  Rumford  has 
proposed  to  determine  the  same  by  the 


*Karsten’s  Eiscnhiittenkunde,  vol.  ii.;  p.  219,  § 476. 
11 


122 


THE  ASSATER’S  GUIDE. 


direct  use  of  a thermometer  in  a closed 
vessel.  Berthier  has,  however,  proposed 
one  that  seems  equally  simple,  and  service- 
able for  all  practical  purposes. 

According  to  his  proposition,  one  gramme 
of  the  coal  (or  other  fuel;  for  it  is  applica- 
ble to  all)  should  be  thoroughly  pulverized. 
All  coals  are  readily  reduced  to  such  a 
state.  Wood  should  be  used  as  shavings,  or 
rasped.  The  powdered  substance  is  then 
mixed  with  some  litharge,  but  more  than 
it  is  capable  of  reducing,— not  less  than 
twenty  times  its  own  weight  nor  more  than 
forty.  The  quality  of  the  fuel  will  enable 
the  assayer,  after  a little  practice,  to  deter- 
mine a priori  with  considerable  accuracy 
what  will  be  the  requisite  quantity.  The 
mixture  is  placed  in  a clay  crucible  (Plate 
II.,  fig.  4 or  5)  and  carefully  covered  with 
about  twenty  to  thirty  grammes  of  litharge. 
The  crucible  must  not  be  filled  over  one- 
half.  This  is  then  placed  in  a heated  muffle 
and  covered.  The  heat  should  not  be  too 


CALORIFIC  POWER  OF  COAL. 


123 


severe  and  rapid.  The  contents  will  boil 
up.  When  the  melting  has  thoroughly 
taken  place,  strong  heat  should  be  applied 
for  ten  minutes,  so  that  the  button  may 
collect.  The  crucible  is  then  taken  out  and 
cooled  slowly,  then  broken,  and  the  button 
extracted  and  weighed. 

This  process  rests  upon  the  fact  that  the 
carbon  will  reduce  the  litharge ; and  having, 
therefore,  assumed  one  number  for  the 
amount  of  litharge  reduced,  from  which 
to  calculate  our  experiments,  it  will  be  easy 
to  compare  the  different  varieties  of  fueh 
When  many  experiments  of  this  kind  are 
made,  the  assayer  will  do  well  to  establish 
a certain  number  as  the  basis.  This  will 
vary  according  to  the  general  character  of 
his  coals.  This  number  it  will  be  well  to 
assume  as  low  as  possible,  to  avoid  the  in- 
convenience of  fractions.  He  would  there- 
fore adopt  a very  inferior  variety  of  coal 
as  the  one  with  which  to  compare  the 
others  in  the  following  manner,  though 


124 


THE  ASSAYER’S  GUIDE. 


be  it  remembered  I am  not  now  giving 
results  of  assays,  but  only  imaginary 
examples. 

1 part  bone-coal  reduced  10.00  parts  by  weight  of  lithaige 

“ rough  bituminous  44  12.50  44  “ 44 

44  good  bituminous  44  20.00  44  44  • 

44  anthracite  44  25.00  44  44  4 


125 


ll* 


Table  of  Analyses  of  different  Clays,  from  which  the  most  approved  Crucibles  are  made. 


126 


Table  showing , in  Degrees  of  the  Centigrade  and  Fah • 
renheit  Thermometers , the  Amount  of  Heat  necessary 
to  melt  various  Substances. 


Centigrade. 

Fahrenheit. 

Platina .... 

2500 

4532 

Bar  Iron . . 

1500-1600 

2732-3012 

Steel 

1300-1400 

2372-2552 

Cast  iron,  gray........ 

1200 

2192 

Do. 

white....... 

1050 

1922 

Gold.. 

1100-1250 

2012-2282 

Silver 

1000 

1832 

Bronze 

900 

1652 

Antimony . 

450 

842 

Zinc 

360 

680 

Lead 

330 

658 

Bismuth... 

260 

480 

Tin 

230 

446 

Alloys  of  Tin, 

Lead,  and 

Bismuth. 

(in  parts.) 

(in  parts.) 

(in  parts.) 

1 

3 

_ 

289 

554 

1 

1 

_ 

241 

464 

3 

_ 

1 

200 

392 

3 

1 

_ 

186 

365 

2 

— 

1 

167.7 

333.5 

S 1 

_ 

1 

142.2 

283.8 

4 

1 

5 

188-9 

246.2 

! 3 

2 

5 

100 

212 

3 

5 

8 

100 

212 

1 

1 

4 

94 

203 

Sulphur... 

109 

230 

Mercury . . 

39 

38.2 

127 


Table  of  Troy  Weights  used  with  Gold , and  Silver , and 
Platina.  * 

24  grains  (gr.)  make,!  pennyweight  (dwt.) 

20  pennyweights  — 1 ounce  (oz.) 

12  ounces  — 1 pound  (lb.) 

lb.  oz.  dwt.  gr. 

1 = 12  = 240  = 5760 

1 = 20  = 480 

1 = 24 

The  value  of  gold  is  given  in  carats  fine,  24  c.  f.  being 
pure. 

One  pound  of  gold  24  carats  fine  contains  5760  grs.  of  pure 
gold,  as  gold  of  that  number  of  carats  fine  is  unalloyed. 

One  pound  of  gold  23  carats  fine  contains  5520  grs.,  and 
-so  on,  and  one  oz.  of  gold  20  c.  f.  has  400  grs. 

one  dwt.  of  gold  15  c.  f.  has  15  grs. 

These  are  given  as  examples  of  the  manner  in  which  the 
amount  of  the  pure  metal  ought  to  be  calculated. 


Table  of  Avoirdupois  Weights  used  with  other  Metals. 

(Tun,)  (Hundredweight)  (Quarter)  (Pound)  (Ounce)  (Dram) 

T.  cwt.  qr.  lb.  oz.  dr. 

1 = 20  ==  80  = 2240  = 35840  = 573440 

1 = 4 = 112  = 1792  = 28672 

1 = 28  = 448  = 7168 

1 = 16  = 256 

1 = 16 


128 


A Table  of  Comparison  of  Twelve  different  National 


Pound 

Avoirdupois. 

Austrian 

Pound. 

Bavarian 

Pound. 

Saxon  (or 
Soil.)  Pound. 

Wurtemburg 

Pound. 

Old  Cologne 
Mark. 

1 

0.80998 

9.90847 

0.81000 

9.90848 

0.90720 

9.95770 

0.96979 

9.98668 

1.94001 

0.28780 

1.23460 

0.09153 

1 

1.00002 

0.00001 

1.12002 

0.04923 

1.19730 

0.07820 

2.39514 

0.37933 

1.23457 

0.09152 

0.99998 

9.99999 

1 

1.12000 

0.04922 

1.19728 

0.07819 

2.39508 

0.37932 

1.10230 

0.04230 

0.89284 

9.95077 

0.89286 

9.95078 

1 

1.06900 

0.02898 

2.13847 

0.33010 

1.03115 

0.01332 

0.83521 

9.92180 

0.83523 

9.92181 

0.93546 

9.97102 

1 

2.00044 

0.30113 

0.51546 

9.71220 

0.41751 

9.62067 

0.41752 

9.62068 

0.46762 

9.66990 

0.49989 

9.69887 

1 

1.10078 

0.04170 

0.89160 

9.95017 

0.89162 

9.95618 

0.99862 

9.99940 

1.06752 

0.02838 

2.13551 

0.32950 

0.93770 

9.97206 

0.75952 

9.88054 

0.75953 

9.88055 

0.85068 

9.92977 

0.90937 

9.95874 

1.81915 

0.25987 

1.07916 

0.03309 

0.87410 

9.94156 

0.87412 

9.94157 

0.97901 

9.99079 

1.04656 

0.01976 

2.09359 

0.32089 

2.20460 

0.34333 

1.78568 

0.25180 

1.78571 

0.25181 

2.00000 

0.30103 

2.13800 

0.33001 

4.27693 

0.63113 

0.90283 

9.95560 

0.73127 

9.86408 

0.73129 

9.86409 

0.81904 

9.91331 

0.87555 

9.94228 

1.75149 

0.24341 

1.03111 

0.01331 

0.83518 

9.92178 

0.83520 

9.92179 

0.93542 

9.97101 

0.99996 

9.99998 

2.00037 

0.30111 

129 


Weights , icith  the  Logarithms  under  each  Number* 


Danish  and 
Norwegian 
Pound. 

Swedish 

Pound. 

Old  French 
Pound, 
(poids  du 
marc.) 

French  Kilo- 
gramme. 

Russian 

Pound. 

(pud.) 

Prussian 

Pound. 

0.90845 

9.95830 

1.06644 

0.02793 

0.92664 

0.96691 

0.45360 

9.65667 

1.10763 

0.04440 

0.96982 

9.98669 

1.12157 

0.04983 

1.31662 

0.11946 

1.14404 

0.05844 

0.56001 

9.74820 

1.36748 

0.13592 

1.19735 

0.07822 

1.12155 

0.04982 

1.31660 

0.11945 

1.14401 

0.05843 

9.56000 

9.74819 

1.36746 

0.13591 

1.19732 

0.07821 

1.00138 

0.00060 

1.17553 

0.07023 

1.02144 

0.00921 

0.50000 

9.69897 

1.22094 

0.08669 

1.06904 

0.02899 

0.93675 

9.97162 

1.09966 

0.04126 

0.95551 

9.98024 

0.46773 

9.66999 

1.14214 

0.05772 

1.00004 

0.00002 

0.46827 

9.67050 

0.54971 

9.74013 

0.47765 

9.67911 

0.23381 

9.36887 

0.57094 

9.75659 

0.49991 

9.69889 

1 

1.17391 

0.06963 

1.02003 

0.00861 

0.49931 

9.69837 

1.21925 

0.08609 

1.06756 

0.02839 

0-85186 

9.93037 

1 

0.86892 

9.93893 

0.42534 

9.62874 

1.03863 

0.01646 

0.90941 

9.95876 

0.98037 

9.99139 

1.15086 

0.06102 

1 

0.48951 

9.68976 

1.19532 

0.07748 

1.04660 

0.01978 

2.00277 

0.30163 

2.35106 

0.37126 

2.04288 

0.31034 

1 

2.44188 

0.38772 

2.13807 

0.33002 

0.8017 

9.91391 

0.96281 

9.98354 

0.83660 

9.92252 

0.40952 

9.61228 

1 

9.87558 

9.94230 

0.93672 

9.97161 

1.09962 

0.04124 

0.95548 

9.98022 

0.46771 

9.66998 

1.14210 

0.05770 

1 

* Taken  from  Weisbach’s  Ingenieur. 


INDEX 


Ag\te  mortar 

Agricola 

Alloys,  of  gold, 

of  silver,  &c. . 

Antimony  in  copper. . 

Aqua  regia 

Arsenic  in  copper 

Arsenious  acid 

Balance 

Bellows  furnace 

Besanite 

Berthier 

Berzelius 

Bismuth  in  copper.... 
Black  flux............... 

Blowpipe 

Bodeman 

Borax.... 

Carats  fine 

Clausthal  assay  office 

Coal 

Cobalt  in  copper... 

Coins 

Coins,  table  of 

Cooling  pan 

Copperas 

Copper  )res... 


PAGE 

40 

15 

71 

68 

90 

66 

90 

84 

28 

23 

71 

7 

7 

........  90 

86 

.......  6 

8 

40 

72 

25 

121 

90 

, 68  to  76 

75 

35,  45,  94 

67 

..85  to  96 
131 


132 


INDEX, 


PAGE 

Cromsted 7 

Crucibles 30 

Cupellation 39 

Cupels 30  to  35 

D’Arcet 69,  73 

D’Arcet’s  table . 74 

English  method  for  copper 92 

Erker’s  table 69 

Freiberg 28 

JFritsche 8 

Gahn 7 

Gay-Lussac’s  process 54 

German  and  Hungarian  silver  assay 85 

Gold  and  Quartz 77 

Gold  coins 71 

Gold  ores,  by  amalgamation 61 

by  heat 56 

by  washing 63 

by  wet  process 66 

Graphite . 85 

Hartz  iron  furnace 104 

Hessian  crucible 33 

Implements  and  utensils 17 

Inquartation  silver 57,  82 

Introduction 13 

Iron  muffle 27 

Iron  ores,  Fuchs’s  process 108 

by  heat 103 

Iron  vitriol 67 

Lead  in  copper 90 

Lead  ores,  by  heat 97 

by  wet  process 100 

Lime  in  silver  ores 43 

Litharge 69 

Luhme  & Co 27,  28 

Mercury,  assay  of. Ill 

Mortar,  iron.. 39 


INDEX. 


133 


PAGE 

Movable  furnace . 2Q 

Muffle........ 17 

Muffle  furnace 17 

Nickel  in  copper 90 

Oxide  of  antimony 87 

Parisian  mint 50 

Peroxide  and  protoxide  of  iron... 108 

Platinum 80 

Platner 7,  23 

Pure  iron 106 

Pure  lead. 40 

Pure  silver 57 

Pyrites,  iron,  in  gold 65 

Quartation. 58 

Quicksilver,  how  cleansed 61 

assay  of Ill 

Silberblick 46 

Silver  coins 68 

Silver  ores 39 

Sulphur 82 

Sulphurets,  assay  of 119 

Table  of  analysis  of  different  clays 125 

Table  of  loss 52 

Table  of  melting  temperature  of  different  metals 126 

Table  of  national  weights 127 

Table  of  Troy  weights 128 

Tin  in  copper 90 

Tin  in  silver 43 

To  find  the  proportion  of  gold  in  gold  and  quartz  ....  77 

Tongs...... 36  to  38 

Touchstone 71 

Ventilation  of  furnace 24 

Washing  gold 63 

White  flux 93 

Zinc  in  silver  ores 43 


THE  END. 
12 


Plate  I.— Part  I. 


ft 


Plate  I. — Part  II. 


Plate  II 


Part  I 


CATALOGUE 

O F 


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Polishing,  etc.  By  Oliver  Byrne.  Illustrated  by  185  wood  en- 
gravings. In  one  volume,  8vo $5.00 

BYRNE.— Pocket  Book  for  Railroad  and  Civil  Engi- 
neers : 

Containing  New,  Exact,  and  Concise  Methods  for  Laying  out  Rail- 
road Curves,  Switches,  Frog  Angles,  and  Crossings;  the  Staking 
out  of  work;  Levelling;  the  Calculation  of  Cuttings;  Embankments; 
Earth- work,  etc.  By  Oliver  Byrne.  18mo.,  full  bound,  pocket- 
book  form . . $1.75 

BYRNE. — The  Practical  Model  Calculator : 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work,  Naval 
Architect,  Miner,  and  Millwright.  By  Oliver  Byrne.  1 volume, 
8vo.,  nearly  600  pages $4.50 

BYRNE.— The  Practical  Metal-Worker’s  Assistant: 

Comprising  Metallurgic  Chemistry;  the  Arts  of  Working  all  Metals 
and  Alloys ; Forging  of  Iron  and  Steel ; Hardening  and  Tempering ; 
Melting  and  Mixing;  Casting  and  Founding;  Works  in  Sheet  Metal; 
The  Processes  Dependent  on  the  Ductility  of  the  Metals;  Soldering; 
and  the  most  Improved  Processes  and  Tools  employed  by  Metal- 
Workers.  With  the  Application  of  the  Art  of  Electro-Metallurgy  to 
Manufacturing  Processes ; collected  from  Original  Sources,  and  from 
the  Works  of  Holtzapffel,  Bergeron,  Leupold,  Plunder,  Napier, 
ScofFern,  Clay,  Fairbairn,  and  others.  By  Oliver  Byrne.  A new, 
revised,  and  improved  edition,  to  which  is  added  An  Appendix,  con- 
taining The  Manufacture  of  Russian  Sheet-Iron.  By  John 
Percy,  M.  D.,  F.R.S.  The  Manufacture  of  Malleable  Iron 
Castings,  and  Improvements  in  Bessemer  Steel.  By  A.  A. 
Fesquet,  Chemist  and  Engineer.  With  over  600  Engravings,  illus- 
trating every  Branch  of  the  Subject.  8vo $7.00 

Cabinet  Maker’s  Album  of  Eurniture : 

Comprising  a Collection  of  Designs  for  Furniture.  Illustrated  by  48 
Large  and  Beautifully  Engraved  Plates.  In  one  vol.,  oblong  $3.50 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


7 


CALLINGS  AM.— Sign  Writing  and  Glass  Emboss- 
ing: 

A Complete  Practical  Illustrated  Manual  of  the  Art.  By  James 
Callingham.  In  one  volume,  12mo $1.50 

CAMPIN. — A Practical  Treatise  on  Mechanical  Engi- 
neering : 

Comprising  Metallurgy,  Mouldipg,  Casting,  Forging,  Tools,  Work- 
shop Machinery,  Mechanical  Manipulation,  Manufacture  of  Steam- 
engines,  etc.,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and 
Iron  Ores.  By  Feancis  Campin,  C.  E.  To  which  are  added,  Obser- 
vations on  the  Construction  of  Steam  Boilers,  and  Remarks  upon 
Furnaces  used  for  Smoke  Prevention ; with  a Chapter  on  Explosions. 
By  R.  Armstrong,  C.  E.,  and  John  Bourne.  Rules  for  Calculating 
the  Change  Wheels  for  Screws  on  a Turning  Lathe,  and  for  a Wheel- 
cutting Machine.  By  J.  La  Nice  a.  Management  of  Steel,  Includ- 
ing Forging,  Hardening,  Tempering,  Annealing,  Shrinking,  and  Ex- 
pansion. And  the  Case-hardening  of  Iron.  By  G.  Ede.  8vo.  Illus- 
trated with  29  plates  and  100  wood  engravings  . . . $6.00 

C AMPIN.— The  Practice  of  Hand-Turning  in  Wood, 
Ivory,  Shell,  etc. : 

With  Instructions  for  Turning  such  works  in  Metal  as  may  be  re- 
quired in  the  Practice  of  Turning  Wood,  Ivory,  etc.  Also,  an  Appen- 
dix on  Ornamental  Turning.  By  Feancis  Campin  ; with  Numerous 
Illustrations.  12mo.,  cloth $3.00 

CAREY. — The  Works  of  Henry  C.  Carey: 

FINANCIAL  CRISES,  their  Causes  and  Effects.  8vo.  paper  . 25 

HARMONY  OF  INTERESTS : Agricultural,  Manufacturing,  and 

Commercial.  8vo.,  cloth $1.50 

MANUAL  OF  SOCIAL  SCIENCE.  Condensed  from  Carey’s  “ Prin- 
ciples of  Social  Science.”  By  Kate  McKean.  1 vol.  12mo.  $2.25 
MISCELLANEOUS  WORKS  : comprising  “ Harmony  of  Interests,” 
“ Money,”  “ Letters  to  the  President,”  “ Financial  Crises,”  “ The 
Way  to  Outdo  England  Without  Fighting  Her,”  “Resources  of 
the  Union,”  “The  Public  Debt,”  “Contraction  or  Expansion?” 
“ Review  of  the  Decade  1857-  67 ,”  “ Reconstruction,”  etc.,  etc. 

Two  vols.,  8vo.,  cloth 

PAST,  PRESENT,  AND  FUTURE.  8vo $2.50 

PRINCIPLES  OF  SOCIAL  SCIENCE.  3 vols.,  8vo.,  cloth  $10.00 
THE  SLAVE-TRADE,  DOMESTIC  AND  FOREIGN ; Why  it  Ex- 
ists, and  How  it  may  be  Extinguished  (1853).  8vo.,  cloth  . $2.00 
LETTERS  ON  INTERNATIONAL  COPYRIGHT  (1867)  . 50 

THE  UNITY  OF  LAW  : As  Exhibited  in  the  Relations  of  Physical, 
Social,  Mental,  and  Moral  Science  (1872).  In  one  volume,  Kvo., 
pp.  xxiii.,  433.  Cloth $3.50 

CHAPMAN. — A Treatise  on  Ropemaking : 

As  Practised  in  private  and  public  Rone  yards,  with  a Description 
of  the  Manufacture,  Rules,  Tables  of  Weights,  etc.,  adapted  to  the 
Trades,  Shipping,  Mining,  Railways,  Builders,  etc.  By  Robert 
Chapman.  24mo $1.50 


8 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


COLBURN. — The  Locomotive  Engine  : 

Including  a Description  of  its  Structure,  Rules  for  Estimating  its  Capa- 
bilities, and  Practical  Observations  on  its  Construction  and  Manage- 
ment. By  Zeeah  Colburn.  Illustrated.  A new  edition.  12mo.  $1.25 

CRAIK.  — The  Practical  American  Millwright  and 
Miller. 

By  David  Craik,  Millwright.  Illustrated  by  numerous  wood  en- 
gravings, and  two  folding  plates.  8vo $5.00 

DE  GRAFF.— The  Geometrical  Stair  Builders’  Guide : 

Being  a Plain  Practical  System  of  Hand-Railing,  embracing  all  its 
necessary  Details,  and  Geometrically  Illustrated  by  22  Steel  Engrav- 
ings ; together  with  the  use  of  the  most  approved  principles  of  Prac- 
tical Geometry.  By  Simon  De  Geaff,  Architect.  4to.  . $5.00 

PE  KONINCK.— DIETZ.— A Practical  Manual  of  Che- 
mical Analysis  and  Assaying : 

As  applied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iron, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  De  Kon- 
inck,  Dr.  Sc.,  and  E.  Dietz,  Engineer.  Edited  with  Notes,  by  Robert 
Mallet,  F.R.S.,  F.S.G.,  M.I.C.E.,  etc.  American  Edition,  Edited 
with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A.  Fesquet,  Chemist 
and  Engineer.  One  volume,  12mo. $2.50 

DUNC AN.— Practical  Surveyor’s  Guide: 

Containing  the  necessary  information  to  make  any  person,  of  common 
capacity,  a finished  land  surveyor  without  the  aid  of  a teacher.  By 
Andrew  Duncan.  Illustrated.  12mo.,  cloth.  . . . $1.25 

DUPLAIS.— A Treatise  on  the  Manufacture  and  Dis- 
tillation of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regard  to  Alcohol  from 
Wine,  Molasses,  Beets,  Grain,  Rice,  Potatoes,  Sorghum,  Asphodel, 
Fruits,  etc.  ; with  the  Distillation  and  Rectification  of  Brandy,  Whis- 
key, Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Preparation  of  Aromatic  Wa- 
ters, Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic  Tinctures, 
Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc.,  the  Aging  of  Brandy 
and  the  Improvement  of  Spirits,  with  Copious  Directions  and  Tables 
for  Testing  and  Reducing  Spirituous  Liquors,  etc.,  etc.  Translated 
and  Edited  from  the  French  of  MM.  Dfplais,  Aine  et  Jeune.  By 
M.  McKennie,  M.D.  To  which  are  added  the  United  States  Internal 
Revenue  Regulations  for  the  Assessment  and  Collection  of  Taxes  on 
Distilled  Spirits.  Illustrated  by  fourteen  folding  plates  and  several 
wood  engravings.  743  pp.,  8vo.  ......  $10.00 

DUSSAUCE. — A General  Treatise  on  the  Manufacture 
of  Every  Description  of  Soap : 

Comprising  the  Chemistry  of  the  Art,  with  Remarks  on  Alkalies,  Sa- 
ponifiable Fatty  Bodies,  the  apparatus  necessary  in  a Soap  Factory, 
Practical  Instructions  in  the  manufacture  of  the  various  kinds  of  Soap, 
the  assay  of  Soaps,  etc.,  etc.  Edited  from  Notes  of  Larme,  Fontenelle, 
Malapayre,  Dufour,  and  others,  with  large  and  important  additions  by 
Prof.  H.  Dussauce,  Chemist.  Illustrated.  In  one  vol.,  8vo,  . $12.50 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


9 


DUSSAUCE.— A General  Treatise  on  the  Manufacture 
of  Vinegar : 

Theoretical  and  Practical.  Comprising  the  various  Methods,  by  the 
Slow  and  the  Quick  Processes,  with  Alcohol,  Wine,  Grain,  Malt,  Cider, 
Molasses,  and  Beets  ; as  well  as  the  Fabrication  of  Wood  Vinegar,  etc., 
eic.  By  Prof.  H.  Dussauce.  In  one  volume,  8vo.  . . $5.00 

DUSSAUCE. — A New  and  Complete  Treatise  on  the 
Arts  of  Tanning,  Currying,  and  Leather  Dressing : 

Comprising  all  the  Discoveries  and  Improvements  made  in  France, 
Great  Britain,  and  the  United  States.  Edited  from  Notes  and  Docu- 
ments of  Messrs.  Sallerou,  Grouvelle,  Duval,  Dessables,  Labarraque, 
Payen,  Rene,  De  Fontenelle,  Malapeyre,  etc.,  etc.  By  Prof.  H.  Dus- 
SAUCE,  Chemist.  Illustrated  by  212  wood  engravings.  8vo.  $25.00 

DUSSAUCE.— A Practical  Guide  for  the  Perfumer  : 

Being  a New  Treatise  on  Perfumery,  the  most  favorable  to  the  Beauty 
without  being  injurious  to  the  Health,  comprising  a Description  of  the 
substances  used  in  Perfumery,  the  Formulae  of  more  than  1000  Prepa- 
rations, such  as  Cosmetics,  Perfumed  Oils,  Tooth  Powders,  Waters, 
Extracts,  Tinctures,  Infusions,  Spirits,  Vinaigres,  Essential  Oils,  Pas- 
tels, Creams,  Soaps,  and  many  new  Hygienic  Products  not  hitherto 
described.  Edited  from  Notes  and  Documents  of  Messrs.  Debay,  Ln- 
nel,  etc.  With  additions  by  Prof.  H.  Dussauce,  Chemist.  12mo. 

DUSSAUCE.— Practical  Treatise  on  the  Fabrication 
of  Matches,  Gun  Cotton,  and  Fulminating  Powders. 

By  Prof.  H.  Dussauce.  12mo $3.00 

Dyer  and  Color-maker’s  Companion: 

Containing  upwards  of  200  Receipts  for  making  Colors,  on  the  most 
approved  principles,  for  all  the  various  styles  and  fabrics  now  in  exist- 
ence; with  the  Scouring  Process,  and  plain  Directions  for  Preparing, 
Washing-off,  and  Finishing  the  Goods.  In  one  vol.,  12mo.  . $1.25 

EASTON.— A Practical  Treatise  on  Street  or  Horse- 
power Railways.  ' 

By  Alexander  Easton,  C.  E.  Illustrated  by  23  plates.  8vo., 
cloth $3.00 

ELDER.— Questions  of  the  Day: 

Economic  and  Social.  By  Dr.  William  Elder.  8vo.  . $3.00 

FAIRBAIRN.— The  Principles  of  Mechanism  and  Ma- 
chinery of  Transmission : 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pulleys, 
Strength  and  Proportions  of  Shafts,  Coupling  of  Shafts,  and  Engaging 
and  Disengaging  Gear.  By  Sir  William  Fairrairn,  C.E.,  LL.l)., 
F.R.S.,  F.G.S.  Beautifully  illustrated  by  over  150  wood-cuts.  In 
one  volume,  $2.50 

FORSYTH.— Book  of  Designs  for  Headstones,  Mural, 

and  other  Monuments : 

Containing  78  Designs.  By  James  Forsyth.  With  an  Introduction 
by  Charles  Boutkll,  M.  A,  4to.,  cloth $5.00 


10 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


GIBSON. — The  American  Dyer: 

A Practical  Treatise  on  the  Coloring  of  Wool,  Cotton,  Yarn  and 
Cloth,  in  three  parts.  Part  First  gives  a descriptive  account  of  the 
Dye  Stuffs ; if  of  vegetable  origin,  where  produced,  how  cultivated, 
and  how  prepared  for  use ; if  chemical,  their  composition,  specific 
gravities,  and  general  adaptability,  how  adulterated,  and  how  to  de- 
tect the  adulterations,  etc.  Part  Second  is  devoted  to  the  Coloring  of 
Wool,  giving  recipes  for  one  hundred  and  twenty-nine  different  colors 
or  shades,  and  is  supplied  with  sixty  colored  samples  of  Wool.  Part 
Third  is  devoted  to  the  Coloring  of  Raw  Cotton  or  Cotton  Waste,  for 
mixing  with  Wool  Colors  in  the  Manufacture  of  all  kinds  of  Fabrics, 
gives  recipes  for  thirty-eight  different  colors  or  shades,  and  is  supplied 
with  twenty-four  colored  samples  of  Cotton  Waste.  Also,  recipes  for 
Coloring  Beavers,  Doeskins,  and  Flannels,  with  remarks  upon  Ani- 
lines, giving  recipes  for  fifteen  different  colors  or  shades,  and  nine 
samples  of  Aniline  Colors  that  will  stand  both  the  Fulling  and  Scour- 
ing process.  Also,  recipes  for  Aniline  Colors  on  Cotton  Thread,  and 
recipes  for  Common  Colors  on  Cotton  Yarns.  Embracing  in  all  over 
two  hundred  recipes  for  Colors  and  Shades,  and  ninety-four  samples 
of  Colored  Wool  and  Cotton  Waste,  etc.  By  Richard  H.  Gibson, 
Practical  Dyer  and  Chemist.  In  one  volume,  8vo.  . . $6.00 

GILBART.— History  and  Principles  of  Banking  : 

A Practical  Treatise.  By  James  W.  Gilbart,  late  Manager  of  the 
London  and  Westminster  Bank.  With  additions.  In  one  volume, 
8vo.,  600  pages,  sheep $5.00 

Gothic  Album  for  Cabinet  Makers : 

Comprising  a Collection  of  Designs  for  Gothic  Furniture.  Illustrated 
by  23  large  and  beautifully  engraved  plates.  Oblong  . . $2.00 

GRANT.  — Beet-root  Sugar  and  Cultivation  of  the 
Beet. 

By  E.  B.  Grant.  12mo $1.25 

GREGORY.— Mathematics  for  Practical  Men  : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and 
Civil  Engineers.  By  Olinthus  Gregory.  8vo.,  plates,  cloth  $3.0(1 

GRISWOLD.— Railroad  Engineer’s  Pocket  Compan- 
ion for  the  Field : 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles, 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  Engi- 
neers ; also  the  art  of  Levelling  from  Preliminary  Survey  to  the  Con- 
struction of  Railroads,  intended  Expressly  for  the  Young  Engineer, 
together  with  Numerous  Valuable  Rules  and  Examples.  By  W. 
Griswold.  12mo.,  tucks $1.75 

GRTJNER.— Studies  of  Blast  Furnace  Phenomena. 

By  M.  L.  Gruner,  President  of  the  General  Council  of  Mines  of 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines. 
Translated,  with  the  Author’s  sanction,  with  an  Appendix,  by  L.  D.  B. 
Gordon,  F.  R.  S.  E„  F.  G,  •«.  Illustrated.  8vo.  . . . $2.50 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


1). 


GUETTIER.— Metallic  Alloys: 

Being  a Practical  Guide  to  their  Chemical  and  Physical  Properties, 
their  Preparation,  Composition,  and  Uses.  Translated  from  the 
French  of  A.  Guettier,  Engineer  and  Director  of  Foundries,  author 
of  “La  Fouderie  en  France,”  etc.,  etc.  By  A.  A.  Fesquet,  Chemist 
and  Engineer.  In  one  volume,  12mo $3.00 

HARRIS. — Gas  Superintendent’s  Pocket  Companion. 

By  Harris  & Brother,  Gas  Meter  Manufacturers,  1115  and  1117 
Cherry  Street,  Philadelphia.  Full  bound  in  pocket-book  form  $1,00 

Hats  and  Pelting: 

A Practical  Treatise  on  their  Manufacture.  By  a Practical  Hatter. 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  . . . $1.25 

HOFMANN. — A Practical  Treatise  on  the  Manufac- 
ture of  Paper  in  all  its  Branches. 

By  Carl  Hofmann.  Late  Superintendent  of  paper  mills  in  Ger- 
many and  the  United  States;  recently  manager  of  the  Public  Ledger 
Paper  Mills,  near  Elkton,  Md.  Illustrated  by  110  wood  engravings, 
and  five  large  folding  plates.  In  one  volume,  4to.,  cloth;  398 
pages $15,00 

HUGHES.— American  Miller  and  Millwright’s  Assist- 
ant. 

By  Wm.  Carter  Hughes.  A new  edition.  In  one  vol.,  12mo.  $1.50 

IIURST.— A Hand-Book  for  Architectural  Surveyors 
and  others  engaged  in  Building: 

Containing  Formulae  useful  in  Designing  Builder’s  work,  Table  of 
Weights,  of  the  materials  used  in  Building,  Memoranda  connected 
with  Builders’  work,  Mensuration,  the  Practice  of  Builders’  Measure- 
ment, Contracts  of  Labor,  Valuation  of  Property,  Summary  of  the 
Practice  in  Dilapidation,  etc.,  etc.  By  J.  F.  IIurst,  C.  E.  Second 
edition,  pocket-book  form,  full  bound $2.00 


JERVIS.— Railway  Property : 

A Treatise  on  the  Construction  and  Management  of  Railways ; de- 
signed to  afford  useful  knowledge,  in  the  popular  style,  to  the  holders 
of  this  class  of  property;  as  well  as  Railway  Managers,  Officers,  and 
Agents.  By  John  B.  JERVIS,  late  Chief  Engineer  of  the  Hudson 
River  Railroad,  Croton  Aqueduct,  etc.  In  one  vol.,  12mo.,  cloth  $2.00 


JOHNSTON.— Instructions  for  tho  Analysis  of  Soils, 
Limestones,  and  Manures. 

By  J.  F.  W.  Johnston,  12mo,  


12 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


KEENE. — A Hand-Book  of  Practical  Ganging : 

For  the  Use  of  Beginners,  to  which  is  added,  A Chapter  on  Distil  la- 
tion,  describing  the  process  in  operation  at  the  Custom  House  l'o r 
ascertaining  the  strength  of  wines.  By  James  B.  Keene,  of  H.  M. 
Customs.  8vo.  , $1.25 

KELLEY.— Speeches,  Addresses,  and  Letters  on  In- 
dustrial and  Financial  Questions. 

By  Hon.  William  D.  Kelley,  M.  C.  In  one  volume,  544  pages, 
8vo $3.00 

KENTISH.— A Treatise  on  a Box  of  Instruments, 

And  the  Slide  Rule ,-  with  the  Theory  of  Trigonometry  and  Loga- 
rithms, including  Practical  Geometry,  Surveying,  Measuring  of  Tim. 
ber,  Cask  and  Malt  Gauging,  Heights,  and  Distances.  By  Thomas 
Kentish.  In  one  volume.  12mo.  .....  $1.25 

KOBELL.— ERNI.— Mineralogy  Simplified : 

A short  Method  of  Determining  and  Classifying  Minerals,  by  means 
of  simple  Chemical  Experiments  in  the  Wet  Way.  Translated  from 
the  last  German  Edition  of  F.  Yon  Kobell,  with  an  Introduction  to 
Blow-pipe  Analysis  and  other  additions.  By  Henri  Eeni,  M.  D., 
late  Chief  Chemist,  Department  of  Agriculture,  author  of  “ Coal  Oil 
and  Petroleum.”  In  one  volume,  f2mo.  ....  $2.50 

LANBRIN— A Treatise  on  Steel: 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  Landrin,  Jr.,  Civil  Engineer.  Translated 
from  the  French,  with  Notes,  by  A.  A.  Fesquet,  Chemist  and  Engi- 
neer. With  an  Appendix  on  the  Bessemer  and  the  Martin  Processes 
for  Manufacturing  Steel,  from  the  Report  of  Abram  S.  Hewitt,  United 
States  Commissioner  to  the  Universal  Exposition,  Paris,  1867.  In  one 
volume,  12mo. $3.00 

LARKIN.— The  Practical  Brass  and  Iron  Founder’s 
Guide : 

A Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  and  their 
Alloys,  etc. : to  which  are  added  Recent  Improvements  in  the  Manu- 
facture of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  By  James 
Larkin,  late  Conductor  of  the  Brass  Foundry  Department  in  Reany, 
Neafie  & Co’s.  Penn  Works,  Philadelphia.  Fifth  edition,  revised, 
with  Extensive  additions.  In  one  volume,  12mo.  . . $2.25 

LEAVITT.— Facts  about  Peat  as  an  Article  of  Fuel : 

With  Remarks  upon  its  Origin  and  Composition,  the  Localities  in 
which  it  is  found,  the  Methods  of  Preparation  and  Manufacture,  and 
the  various  Uses  to  which  it  is  applicable  ; together  with  many  other 
matters  of  Practical  and  Scientific  Interest.  To  which  is  added  a chap- 
ter on  the  Utilization  of  Coal  Dust  with  Peat  for  the  Production  of  an 
Excellent  Fuel  at  Moderate  Cost,  specially  adapted  for  Steam  Service. 
By  T.  H.  Leavitt.  Third  edition.  12mo.  . . . $1.75 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


13 


LEROUX,  C. — A Practical  Treatise  on  the  Manufac- 
ture of  Worsteds  and  Carded  Yarns : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  methods  of  Combing,  Drawing,  and  Spinning  Worsteds 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
Charles  Leroux,  Mechanical  Engineer,  and  Superintendent  of  a 
Spinning  Mill,  by  Horatio  Paine,  M.  D.,  and  A.  A.  F'esquet, 
Chemist  and  Engineer.  Illustrated  by  12  large  Plates.  To  which  is 
added  an  Appendix,  containing  extracts  from  the  Reports  of  the  Inter- 
national Jury,  and  of  the  Artisans  selected  by  the  Committee  appointed 
by  the  Council  of  the  Society  of  Arts,  London,  on  Woollen  and  Worsted 
Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Universal  Exposi- 
tion, 1867.  8vo.,  cloth $5.00 

LESLIE  (Miss).— Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  Leslie. 
60th  thousand.  Thoroughly  revised,  with  the  addition  of  New  Re- 
ceipts. In  one  volume,  12mo.,  cloth $1.50 

LESLIE  (Miss).— Ladies’  House  Book : 

A Manual  of  Domestic  Economy.4  20th  revised  edition.  12mo.,  cloth. 

LESLIE  (Miss). — Two  Hundred  Receipts  in  French 
Cookery. 

Cloth,  12mo. 

LIEBER. — Assayer’s  Guide  : 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
the  principal  Metals,  of  Gold  and  Silver  Coins  and  Alloys,  and  of 
Coal,  etc.  By  Oscar  M.  Lieber.  12mo.,  cloth.  . . $1.25 

LOTH.— The  Practical  Stair  Builder: 

A Complete  Treatise  on  the  Art  of  Building  Stairs  and  Hand-Rails, 
Designed  for  Carpenters,  Builders,  and  Stair-Builders.  Illustrated 
with  Thirty  Original  Plates.  By  C.  Edward  Lotii,  Professional 
Stair-Builder.  One  large  4to.  volume.  ....  $10.00 

LOVE. — The  Art  of  Dyeing,  Cleaning,  Scouring,  and 
Finishing,  on  the  Most  Approved  English  and 
French  Methods: 

Being  Practical  Instructions  in  Dyeing  Silks,  Woollens,  and  Cottons, 
Feathers,  Chips,  Straw,  etc.  Scouring  and  Cleaning  Bed  and  Window 
Curtains,  Carpets,  Bugs,  etc.  French  and  English  Cleaning,  any 
Color  or  Fabric  of  Silk,  Satin,  or  Damask.  Bv  Thomas  Love,  a 
Working  Dyer  and  Scourer.  Second  American  Edition,  to  which  are 
added  General  Instructions  for  the  Use  of  Aniline  Colors.  In  one 
volume,  8vo.,  343  pages. $5.00 


14 


HENRY  CAREY  BAIRD’S  CATALOGUE 


MAIN  and  BROWN. — Questions  on  Subjects  Con- 
nected with  the  Marine  Steam-Engine  : 

And  Examination  Papers : with  Hints  for  their  Solution.  By  Thomas 
J".  Main,  Professor  of  Mathematics,  Royal  Naval  College,  and  Thomas 
Bkown,  Chief  Engineer,  R.  N.  12mo.,  cloth.  . . . ^$1.50 

MAIN  and  BROWN.— The  Indicator  and  Dynamo- 
meter : 

With  their  Practical  Applications  to  the  Steam-Engine.  By  Thomas 
J.  Main,  M.  A.  F.  R.,  Assistant  Professor  Royal  Naval  College,  Ports- 
mouth, and  Thomas  Brown,  Assoc.  Inst.  C.  E.,  Chief  Engineer,  R. 
N.,  attached  to  the  Royal  Naval  College.  Illustrated.  From  the 
Fourth  London  Edition.  8vo. $1.50 

MAIN  and  BROWN.— The  Marine  Steam-Engine. 

By  Thomas  J.  Main,  F.  R. ; Assistant  S.  Mathematical  Professor  at 
the  Royal  Naval  College,  Portsmouth,  and  Thomas  Brown,  Assoc. 
Inst.  C.  E.,  Chief  Engineer  R.  N.  Attached  to  the  Royal  Naval  Col- 
lege. Authors  of  “Questions  connected  with  the  Marine  Steam-En- 
gine,” and  the  “ Indicator  and  Dynamometer.”  With  numerous  Illus- 
trations. In  one  volume,  8vo. $5.00 

MARTIN.— Screw-Cutting  Tables,  for  the  Use  of  Me- 
chanical Engineers : 

Showing  the  Proper  Arrangement  of  Wheels  for  Cutting  the  Threads 
of  Screws  of  any  required  Pitch  ; with  a Table  for  Making  the  Uni- 
versal Gas-Pipe  Thread  and  Taps.  By  W.  A.  Martin,  Engineer. 
8vo 50 

Mechanics’  (Amateur)  Workshop: 

A treatise  containing  plain  and  concise  directions  for  the  manipula- 
tion of  Wood  and  Metals,  including  Casting,  Forging,  Brazing,  Sol- 
dering,  and  Carpentry.  By  the  author  of  the  “Lathe  and  its  Uses.” 
Third  edition.  Illustrated.  8vo ■ $3.00 

MOLES  WORTH. — Pocket-Book  of  Useful  Formulae 
and  Memoranda  for  Civil  and  Mechanical  Engi- 
neers. 

By  Guilford  L.  Molesworth,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident  Engineer  of  the  Ceylon  Railway.  Second 
American,  from  the  Tenth  London  Edition.  In  one  volume,  full 
bound  in  pocket-book  form $2.00 

NAPIER. — A System  of  Chemistry  Applied  to  Dyeing. 

By  James  Napier,  F.  C.  S.  A New  and  Thoroughly  Revised  Edi- 
tion. Completely  brought  up  to  the  present  state  of  the  Science,  inclu- 
ding the  Chemistry  of  Coal  Tar  Colors,  by  A.  A.  Fesquet,  Chemist 
and  Engineer.  With  an  Appendix  on  Dyeing  and  Calico  Printing,  as 
shown  at  the  Universal  Exposition,  Paris,  1867.  Illustrated.  In  one 
Volume,  8vo.,  422  pages.  . . . . . . . . $5.00 


HENRY  CAREY  BAIRD’S  CATALOGUE, 


15 


NAPIER. — Manual  of  Electro-Metallurgy : 

Including  the  Application  of  the  Art  to  Manufacturing  Processes.  By 
James  Napier.  Fourth  American,  from  the  Fourth  London  edition, 
revised  and  enlarged.  Illustrated  by  engravings.  In  one  vol.,  8vo.  $2.00 

NASON. — Table  of  Reactions  for  Qualitative  Chemical 
Analysis. 

By  Henry  B.  Nason,  Professor  of  Chemistry  in  the  Rensselaer  Poly- 
technic Institute,  Troy,  New  York.  Illustrated  by  Colors.  . 03 

NEWBERY- Gleanings  from  Ornamental  Art  of 
every  style : 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  Mher  Museums,  the  Exhibitions  of  1851  and  1862, 
and  the  best  English  and  Foreign  works.  In  a series  of  one  hundred 
exquisitely  drawn  Plates,  containing  many  hundred  examples.  By 
Robert  Newbery.  4to.  .......  $12.50 

NICHOLSON.— A Manual  of  the  Art  of  Bookbinding: 

Containing  full  instructions  in  the  different  Branches  of  Forwarding, 
Gilding,  and  Finishing.  Also,  the  Art  of  Marbling  Book-edges  and 
Paper.  By  James  B.  Nicholson.  Illustrated.  l_mo.,  cloth.  $2.25 

NICHOLSON.— The  Carpenter’s  New  Guide: 

A Complete  Book  of  Lines  for  Carpenters  and  Joiners.  By  Peter 
Nicholson.  The  whole  carefully  and  thoroughly  revised  by  H.  K. 
Davis,  and  containing  numerous  new  and  improved  and  original  De- 
signs for  Roofs,  Domes,  etc.  By  Samuel  Sloan,  Architect.  Illus- 
trated by  80  plates.  4to. 

NORRIS.— A Hand-book  for  Locomotive  Engineers 
and  Machinists: 

Comprising  the  Proportions  and  Calculations  for  Constructing  Loco- 
motives ; Manner  of  Setting  Valves ; Tables  of  Squares,  Cubes,  Areas, 
etc.,  etc.  By  Septimus  Norris,  Civil  and  Meehaiiical  Engineer. 
New  edition.  Illustrated.  12mo.,  cloth $1.50 

NYSTROM.— On  Technological  Education,  and  the 
Construction  of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  John  \V.  Nystrom,  late  Act- 
ing Chief  Engineer,  U.  S.  N.  Second  edition,  revised  with  additional 
matter.  Illustrated  by  seven  engravings.  12mo.  . . $1.50 

O’NEILL. — A Dictionary  of  Dyeing  and  Calico  Print- 
ing: 

Containing  a brief  account  of  all  the  Substances  and  Processes  in  use 
in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics;  with  Practical 
Receipts  and  Scientific  Information.  By  Charles  O’Neill,  Ana- 
lytical Chemist ; Fellow  of  the  Chemical  Society  of  London  ; Member 
of  the  Literary  and  Philosophical  Society  of  Manchester;  Author  of 
“Chemistry  of  Calico  Printing  and  Dyeing.”  To  which  is  added  an 
Essay  on  Coal  Tar  Colors  and  their  application  to  Dyeing  and  Calico 
Printing.  By  A.  A.  FkSQUET,  Chemist  and  Engineer.  With  an  Ap- 
pendix on  Dyeing  and  Calico  Printing,  as  shown  at  the  Universal 
Exposition,  Paris,  1867.  In  one  volume,  8vo.,  491  pages.  . $5.00 


16 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


ORTON. — Underground  Treasures  : 

IIow  and  Where  to  Find  Them.  A Key  for  the  Ready  Determination 
of  all  the  Useful  Minerals  within  the  United  States.  By  James 
Orton,  A.  M.  Illustrated,  12mo $1.50 

OSBORN.— American  Mines  and  Mining: 

Theoretically  and  Practically  Considered.  By  Prof.  H.  S.  Osborn. 
Illustrated  by  numerous  engravings.  8vo.  {In  'preparation.) 

OSBORN.— The  Metallurgy  of  Iron  and  Steel : 

Theoretical  and  Practical  in  all  its  Branches ; with  special  reference 
to  American  Materials  and  Processes.  By  H.  S.  Osborn,  LL.  D., 
Professor  of  Mining  and  Metallurgy  in  Lafayette  College,  Easton, 
Pennsylvania.  Illustrated  by  numerous  large  folding  plates  and 
wood-engravings.  8vo. $15.00 

OVERMAN.— The  Manufacture  of  Steel : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A Handbook  for  Blacksmiths  and  Workers  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware, of  Steel  and  Iron,  and  for  Men  of  Science  and  Art.  By  Fred- 
erick Overman,  Mining  Engineer,  Author  of  the  “ Manufacture  of 
Iron/’  etc.  A new,  enlarged,  and  revised  Edition.  By  A.  A.  Fesquet, 
Chemist  and  Engineer $1.50 

OVERMAN.— The  Moulder  and  Pounder’s  Pocket 
Guide  : 

A Treatise  on  Moulding  and  Founding  in  Green-sand,  Dry-sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow- 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues  ; Description  of  Moulds 
for  Iron,  Bronze,  Brass,  and  other  Metals ; Plaster  of  Paris,  Sulphur, 
Wax,  and  other  articles  commonly  used  in  Casting;  the  Construction 
of  Melting  Furnaces,  the  Melting  and  Founding  of  Metals ; the  Com- 
position of  Alloys  and  their  Nature.  With  an  Appendix  containing 
Receipts  for  Alloys,  Bronze,  Varnishes  and  Colors  for  Castings;  also, 
Tables  on  the  Strength  and  other  qualities  of  Cast  Metals.  By  Fred- 
erick Overman,  Mining  Engineer,  Author  of  “ The  Manufacture 
of  Iron.”  With  42  Illustrations.  12mo $1.50 

Painter,  Gilder,  and  Varnisher’s  Companion: 

Containing  Rules  and  Regulations  in  everything  relating  to  the  Arts 
of  Painting,  Gilding,  Varnishing,  Glass-Staining,  Graining,  Marbling, 
Sign-Writing,  Gilding  on  Glass,  and  Coach  Painting  and  Varnishing; 
Tests  for  the  Detection  of  Adulterations  in  Oils,  Colors,  etc. ; and  a 
Statement  of  the  Diseases  to  which  Painters  are  peculiarly  liable,  with 
the  Simplest  and  Best  Remedies.  Sixteenth  Edition.  Revised,  with 
an  Appendix.  Containing  Colors  and  Coloring  - Theoretical  and 
Practical.  Comprising  descriptions  of  a great  variety  of  Additional 
Pigments,  their  Qualities  and  Uses,  to  which  are  added,  Dryers,  and 
Modes  and  Operations  of  Painting,  etc.  Together  with  Chevreul’s 
Principles  of  Harmony  and  Contrast  of  Colors.  12mo.,  cloth.  $1.50 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


17 


PALLETT.— The  Miller’s,  Millwright’s,  and  Engineer’s 
Guide. 

By  Henry  Pallett.  Illustrated.  In  one  volume,  12mo.  $3.00 

PERCY.— The  Manufacture  of  Russian  Sheet-Iron. 

By  John  Percy,  M.D.,  F.R.S.,  Lecturer  on  Metallurgy  at  the  Royal 
School  of  Mines,  and  to  The  Advanced  Class  of  Artillery  Officers  at 
the  Royal  Artillery  Institution,  Woolwich  ; Author  of  “ Metallurgy.” 
With  Illustrations.  8vo.,  paper 50  cts. 

PERKINS.— Gas  and  Ventilation. 

Practical  Treatise  on  Gas  and  Ventilation.  With  Special  Relation  to 
Illuminating,  Heating,  and  Cooking  by  Gas.  Including  Scientific 
Helps  to  Engineer-students  and  others.  With  Illustrated  Diagrams. 
By  E.  E.  Perkins.  12mo.,  cloth $1.25 

PERKINS  and  STOWE.— A New  Guide  to  the  Sheet- 
iron  and  Boiler  Plate  Roller  : 

Containing  a Series  of  Tables  showing  the  Weight  of  Slabs  and  Piles 
to  produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron;  the  Thickness  of  the  Bar  Gauge  in 
decimals ; the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or  Wire 
Gauge  of  the  fractional  parts  of  an  inch  ; the  Weight  per  sheet,  and 
the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various  dimensions 
to  weigh  112  lbs.  per  bundle;  and  the  conversion  of  Short  Weight 
into  Long  Weight,  and  Long  Weight  into  Short.  Estimated  and  col- 
lected by  G.  H.  Perkins  and  J.  G.  Stowe $2.50 

PHILLIPS  and  DARLINGTON— Records  of  Mining 
and  Metallurgy ; 

Or  Facts  and  Memoranda  for  the  use  of  the  Mine  Agent  and  Smelter. 
By  J.  Arthur  Phillips,  Mining  Engineer,  Graduate  of  the  Imperial 
School  of  Mines,  France,  etc.,  and  John  Darlington.  Illustrated 
by  numerous  engravings.  In  one  volume,  12mo.  . . $1.50 

PRO TEAUX.— Practical  Guide  for  the  Manufacture 
of  Paper  and  Boards. 

By  A.  Proteaux,  Civil  Engineer,  and  Graduate  of  the  School  of  Arts 
and  Manufactures,  and  Director  of  Thiers’  Paper  Mill,  Puy-de-Dome. 
With  additions,  by  L.  S.  Le  NORMAND.  Translated  from  the  French, 
with  Notes,  by  Horatio  Paine,  A.  B.,  M.  I).  To  which  is  added  a 
Chapter  on  the  Manufacture  of  Paper  from  Wood  in  the  United 
States,  by  Henry  T.  Brown,  of  the  “American  Artisan.”  Illus- 
trated by  six  plates,  containing  Drawings  of  Raw  Materials,  Machi- 
nery, Plans  of  Paper-Mills,  etc.,  etc.  8vo.  . . . . $10.00 

RE GN AULT.— Elements  of  Chemistry. 

By  M.  V.  Regnaui.t.  Translated  from  the  French  by  T.  Forrest 
Button,  M.  D.,  and  edited,  with  Notes,  by  James  C.  Booth,  Mel  ter 
and  Refiner  IT.  S.  Mint,  and  Wm.  L.  Faber,  Metallurgist  and  Mining 
Engineer.  Illustrated  by  nearly  700  wood  engravings.  Comprising 
nearly  1500  pages.  In  two  volumes,  8vo.,  cloth.  . . . $7.50 


18 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


REID.— A Practical  Treatise  on  the  Manufacture  of 
Portland  Cement : 

By  Henry  Reid,  C.  E.  To  which  is  added  a Translation  of  M.  A, 
Lipowitz’s  Work,  describing  a New  Method  adopted  in  Germany  for 
Manufacturing  that  Cement,  by  W.  F.  Reid.  Illustrated  by  plates 
and  wood  engravings.  8vo $5.00 

RIFFAULT,  VERGNAUD,  and  TOUSSAINT.— A 
Practical  Treatise  on  the  Manufacture  of  Var- 
nishes. 

By  MM.  Riffault,  Vergnaud,  and  Toussaint.  Revised  and 
Edited  by  M.  F.  Malepeyre  and  Dr.  Emil  Winckler.  Illustrated. 
In  one  volume,  8vo.  {In  'preparation.') 

RIFFAULT,  VERGNAUD,  and  TOUSSAINT.— A 
Practical  Treatise  on  the  Manufacture  of  Colors 
for  Painting : 

Containing  the  best  Formulae  and  the  Processes  the  Newest  and  in 
most  General  Use.  By  M M.  Riffault,  Vergnaud,  and  Toussaint. 
Revised  and  Edited  by  M.  F.  Malepeyre  and  Dr.  Emil  Winckler. 
Translated  from  the  French  by  A.  A.  Fesquet,  Chemist  and  Engi- 
neer. Illustrated  by  Engravings.  In  one  volume,  050  pages,  8vo. 

$7.50 

ROBINSON.— Explosions  of  Steam  Boilers: 

How  they  are  Caused,  and  how  they  may  be  Prevented.  By  «T.  R. 
Robinson,  Steam  Engineer.  12mo $1.25 

ROPER. — A Catechism  of  High  Pressure  or  Non- 
Condensing  Steam-Engines : 

Including  the  Modelling,  Constructing,  Running,  and  Management 
of  Steam  Engines  and  Steam  Boilers.  With  Illustrations.  By 
Stephen  Roper,  Engineer.  Full  bound  tucks  . . . $2.00 

ROSELEUR.— Galvanoplastic  Manipulations : 

A Practical  Guide  for  the  Gold  and  Silver  Electro-plater  and  the 
Galvanoplastic  Operator.  Translated  from  the  French  of  Alfred 
Roseleur,  Chemist,  Professor  of  the  Galvanoplastic  Art,  Manufactu-. 
rer  of  Chemicals,  Gold  and  Silver  Electro-plater.  By  A.  A.  Fesquet, 
Chemist  and  Engineer.  Illustrated  by  over  127  Engravings  on  wood. 

8vo.,  495  pages.  . . . $6.00 

This  Treatise  is  the  fullest  and  by  far  the  best  on  this  subject  ever 
published  in  the  United  States. 

SCHINZ.— Researches  on  the  Action  of  the  Blast 
Furnace. 

By  Charles  Schinz.  Translated  from  the  German  with  the  special 
permission  of  the  Author  by  William  H.  Maw  and  Moritz  Mul- 
ler. With  an  Appendix  written  by  the  Author  expressly  for  this 
edition.  Illustrated  by  seven  plates,  containing  28  figures.  In  one 
volume,  12mo.  . , . $4.00 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


19 


SHAW.— Civil  Architecture : 

Being  a Complete  Theoretical  and  Practical  System  of  Building,  con- 
taining the  Fundamental  Principles  of  the  Art.  By  Edward  Shaw, 
Architect.  To  which  is  added  a Treatise  on  Gothic  Architecture,  etc. 
By  Thomas  W.  Silloway  and  George  M.  Harding,  Architects. 
The  whole  illustrated  by  One  Hundred  and  Two  quarto  plates  finely 
engraved  on  copper.  Eleventh  Edition.  4to.,  cloth.  . $10.00 

SHUNK.— A Practical  Treatise  on  Pailway  Curves 
and  Location,  for  Young  Engineers. 

By  William  F.  Shijnk,  Civil  Engineer.  12mo.  . . $2.00 

SLOAN.— American  Houses : 

A variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by  20 
colored  Engravings,  with  Descriptive  References.  By  Samuel  Sloan, 
Architect,  author  of  the  “ Model  Architect,”  etc.,  etc.  8vo.  $1.50 

SMEATON- Builder’s  Pocket  Companion: 

Containing  the  Elements  of  Building,  Surveying,  and  Architecture ; 
with  Practical  Rules  and  Instructions  connected  with  the  subject. 
By  A.  C.  Smeaton,  Civil  Engineer,  etc.  In  one  volume,  12mo.  $1.50 

SMITH.— A Manual  of  Political  Economy. 

By  E.  Peshine  Smith.  A new  Edition,  to  which  is  added  a full 
Index.  12mo.,  cloth $1.25 

SMITH.— Parks  and  Pleasure  Grounds: 

Or  Practical  Notes  on  Country  Residences,  Villas,  Public  Parks,  and 
Gardens.  By  Charles  H.  J.  Smith,  Landscape  Gardener  and 
Garden  Architect,  etc.,  etc.  12mo. $2.25 

SMITH. — The  Dyer’s  Instructor: 

Comprising  Practical  Instructions  in  the  Art  of  Dyeing  Silk,  Cotton, 
Wool,  and  Worsted,  and  Woollen  Goods:  containing  nearly  800 
Receipts.  To  which  is  added  a Treatise  on  the  Art  of  Padding ; and 
the  Printing  of  Silk  Warps,  Skeins,  and  Handkerchiefs,  and  tho 
various  Mordants  and  Colors  for  the  different  styles  of  such  work. 
By  David  Smith,  Pattern  Dyer.  12mo.,  cloth.  , , . $3.00 

SMITH.— The  Dyer’s  Instructor: 

Comprising  Practical  Instructions  in  the  Art  of  Dyeing  Silk,  Cotton, 
Wool,  and  Worsted  and  Woollen  Goods.  Third  Edition,  with  many 
additional  Receipts  for  Dyeing  the  New  Alkaline  Blues  and  Night 
Greens,  with  Dyed  Patterns  affixed.  12wo.,  pp.  391,  cloth.  . $10.50 

STEWART.— The  American  System. 

Speeches  on  the  Tariff  Question,  and  on  Internal  Improvements,  princi- 
pally delivered  in  the  House  of  Representatives  of  the  United  States. 
By  Andrew  Stewart,  Into  M.  C,  from  Pennsylvania.  With  a Portrait, 
and  a Biographical  Sketch.  In  one  volumo,  8vo.,  407  pages.  $3.00 


20 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


STOKES. — Cabinet-maker’s  and  Upholsterer’s  Com- 
panion : 

Comprising  the  Rudiments  and  Principles  of  Cabinet-making  and  Up- 
holstery, with  Familiar  Instructions,  illustrated  by  Examples  for 
attaining  a Proficiency  in  the  Art  of  Drawing,  as  applicable  to  Cabi- 
net-work; the  Processes  of  Veneering,  Inlaying,  and  Buhl- work  ; the 
Art  of  Dyeing  and  Staining  Wood,  Bone,  Tortoise  Shell,  etc.  Direc- 
tions for  Lackering,  Japanning,  and  Varnishing;  to  make  French 
Polish ; to  prepare  the  Best  Glues,  Cements,  and  Compositions,  and  a 
number  of  Receipts  particularly  useful  for  workmen  generally.  By 
J.  Stokes.  In  one  volume,  l2mo.  With  Illustrations.  . $1.25 

Strength  and  other  Properties  of  Metals: 

Reports  of  Experiments  on  the  Strength  and  other  Properties  of  Metals 
for  Cannon.  With  a Description  of  the  Machines  for  testing  Metals, 
and  of  the  Classification  of  Cannon  in  service.  By  Officers  of  the  Ord- 
nance Department  U.  S.  Army.  By  authority  of  the  Secretary  of  War. 
Illustrated  by  25  large  steel  plates.  In  one  volume,  4to.  . $10.00 

SULLIVAN.— Protection  to  Native  Industry. 

By  Sir  Edward  Sullivan,  Baronet,  author  of  “ Ten  Chapters  on 
Social  Reforms.”  In  one  volume,  8vo.  . . ‘ . . $1.50 

Tables  Showing  the  Weight  of  Pound,  Square, 

Flat  Bar  Iron,  Steel,  ete., 

By  Measurement.  Cloth 

TAYLOR. — Statistics  of  Goal: 

Including  Mineral  Bituminous  Substances  employed  in  Arts  and 
Manufactures ; with  their  Geographical,  Geological,  and  Commercial 
Distribution  and  Amount  of  Production  and  Consumption  on  the 
American  Continent.  With  Incidental  Statistics  of  the  Iron  Manu- 
facture. By  R.  C.  Taylor.  Second  edition,  revised  by  S.  S.  IIal- 
DEMAN.  Illustrated  by  five  Maps  and  many  wood  engravings.  8vo., 
cloth $10.00 

TEMPLETON.— The  Practical  Examinator  on  Steam 
and  the  Steam-Engine: 

With  Instructive  References  relative  thereto,  arranged  for  the  Use  of 
Engineers,  Students,  and  others.  By  Wm.  Templeton,  Engineer. 
12mo.  . $1.25 

THOMAS.— The  Modern  Practice  of  Photography. 

By  R.  W.  Thomas,  F.  C.  S.  8vo.,  cloth 75 

THOMSON.— Freight  Charges  Calculator. 

By  Andrew  Thomson,  Freight  Agent.  24mo.  . . . $1.25 

TURNING:  Specimens  of  Fancy  Turning  Executed 
on  the  Hand  or  Foot  Lathe: 

With  Geometric,  Oval,  and  Eccentric  Chucks,  and  Elliptical  Cutting 
Frame.  By  an  Amateur.  Illustrated  by  30  exquisite  Photographs. 
4to.  ............  $3.00 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


Turner’s  (The)  Companion : 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric  Turn- 
ing : also  various  Plates  of  Chucks,  Tools,  and  Instruments ; and  Di- 
rections for  using  the  Eccentric  Cutter,  Drill,  Vertical  Cutter,  and 
Circular  Rest ; with  Patterns  and  Instructions  for  working  them.  A 
new  edition  in  one  volume,  12mo.  $1.50 

URBIN.— BRTJLL.— A Practical  Guide  for  Puddling 
Iron  and  Steel. 

By  Ed.  Urbin,  Engineer  of  Arts  and  Manufactures.  A Prize  Essay 
read  before  the  Association  of  Engineers,  Graduate  of  the  School  of 
Mines,  of  Liege,  Belgium,  at  the  Meeting  of  1865-0.  To  which  is  added 
A Comparison  op  the  Resisting  Properties  of  Iron  and  Steel. 
By  A.  Brull.  Translated  from  the  French  by  A.  A.  Fesquet,  Che- 
mist and  Engineer.  In  one  volume,  8vo $1.00 

VAILE. — Galvanized  Iron  Cornice- Worker’s  Manual: 

Containing  Instructions  in  Laying  out  the  Different  Mitres,  and  Ma- 
king Patterns  for  all  kinds  of  Plain  and  Circular  Work.  Also,  Tables 
of  Weights,  Areas  and  Circumferences  of  Circles,  and  other  Matter 
calculated  to  Benefit  the  Trade.  By  Charles  A.  Vaile,  Superin- 
tendent “ Richmond  Cornice  Works,”  Richmond,  Indiana.  Illustra- 
ted by  21  Plates.  In  one  volume,  4to $5.00 

VILLE.— The  School  of  Chemical  Manures : 

Or,  Elementary  Principles  in  the  Use  of  Fertilizing  Agents.  From  the 
French  of  M.  George  Ville,  by  A.  A.  Fesquet,  Chemist  and  Engi- 
neer. With  Illustrations.  In  one  volume,  12  mo.  . . $1.25 

VOGDES.— The  Architect’s  and  Builder’s  Pocket  Com- 
panion and  Price  Book: 

Consisting  of  a Short  but  Comprehensive  Epitome  of  Decimals,  Duo- 
decimals, Geometry  and  Mensuration ; with  Tables  of  U.  S.  Measures, 
Sizes,  Weights,  Strengths,  etc.,  of  Iron,  Wood,  Stone,  and  various 
other  Materials,  Quantities  of  Materials  in  Given  Sizes,  and  Dimen- 
sions of  Wood,  Brick,  and  Stone;  and  a full  and  complete  Bill  of 
Prices  for  Carpenter’s  Work;  also,  Rules  tor  Computing  and  Valuing 
Brick  and  Brick  Work,  Stone  Work,  Painting,  Plastering,  etc.  By 
Frank  W.  Vogdes,  Architect.  Illustrated.  Full  bound  in  pocket- 


book  form $2.00 

Bound  in  cloth. 1-50 


WARN— The  Sheet-Metal  Worker’s  Instructor: 

For  Zinc,  Sheet-Iron,  Copper,  and  Tin-Plate  Workers,  etc.  Contain- 
ing a selection  of  Geometrical  Problems;  also,  Practical  and  Simple 
Rules  for  describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  Reuben  II.  Warn,  Practical  r.l  in- 
plate Worker.  To  which  is  added  an  Appendix,  containing  instruc- 
tions for  Boiler  Making,  Mensuration  of  Surfaces  and  Solids,  Rules  lor 
Calculating  the  Weights  of  different  Figures  of  Iron  and  Steel,  Tables 
of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  32  Plates  and  37 
Wood  Engravings.  8vo. $3.00 


22 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


WATSON.— A Manual  of  the  Hand-Lathe : 

Comprising  Concise  Directions  for  working  Metals  of  all  kinds,  Ivory, 
Bone  and  Precious  Woods ; Dyeing,  Coloring,  and  French  Polishing; 
Inlaying  by  Veneers,  and  various  methods  practised  to  produce  Elabo- 
rate work  with  Dispatch,  and  at  Small  Expense.  By  Egbert  P. 
Watson,  late  of  “ The  Scientific  American,”  Author  of  “ The  Modern 
Practice  of  American  Machinists  and  Engineers.”  Illustrated  by  78 
Engravings.  . $1.50 

WATSON. — The  Modern  Practice  of  American  Ma- 
chinists and  Engineers : 

Including  the  Construction,  Application,  and  Use  of  Drills,  Lathe 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow  Work  Generally, 
with  the  most  Economical  Speed  for  the  same  ; the  Results  verified  by 
Actual  Practice  at  the  Lathe,  the  Vice,  and  on  the  Floor.  Together 
with  Workshop  Management,  Economy  of  Manufacture,  the  Steam- 
Engine,  Boilers,  Gears,  Belting,  etc.,  etc.  By  Egbert  P.  Watson, 
late  of  the  “ Scientific  American.”  Illustrated  by  86  Engravings.  In 
one  volume,  12mo . $2.50 

WATSON.— The  Theory  and  Practice  of  the  Art  of 
Weaving  by  Hand  and  Power: 

With  Calculations  and  Tables  for  the  use  of  those  connected  with  the 
Trade.  By  John  Watson,  Manufacturer  and  Practical  Machine 
Maker.  Illustrated  by  large  Drawings  of  the  best  Power  Looms. 
8 vo. $7.50 

WEATHERLY.- Treatise  on  the  Art  of  Boiling  Su- 
gar, Crystallising,  Lozenge-making,  Comfits,  Gum 
Goods. 

12mo $2.00 

WILL. — Tables  for  Qualitative  Chemical  Analysis. 

By  Professor  Heinrich  Will,  of  Giessen,  Germany.  Seven* h edi- 
tion. Translated  by  Charles  F.  Himes,  Ph.  D.,  Professor  of  Natu- 
ral Science,  Dickinson  College,  Carlisle,  Pa.  . . . $1.50 

WILLIAMS. — On  Heat  and  Steam : 

Embracing  New  Views  of  Vaporization,  Condensation,  and  Explosions. 
By  Charles  Wye  Williams,  A.  I.  C.  E.  Illustrated.  8vo.  $3.50 

WOHLER. — A Hand-Book  of  Mineral  Analysis. 

By  F.  Wohler,  Professor  of  Chemistry  in  the  University  of  Gottin- 
gen. Edited  by  Henry  B.  Nason,  Professor  of  Chemistry  in  the 
Rensselaer  Polytechnic  Institute,  Troy,  New  York.  Illustrated.  In 


one  volume,  12mo $3  00 

WORSSAM. — On  Mechanical  Saws: 

From  the  Transactions  of  the  Society  of  Engineers,  1860.  By  S.  W. 
Worssam,  Jr.  Illustrated  by  18  large  plates.  8vo.  . . $o.uO 


HENRY  CAREY  BAIRD’S  CATALOG  (JE. 


23 


REGENT  ADDITIONS  TO  OUR  LIST. 


AUERBACH. — Anthracen  : Its  Constitution,  Properties,  Man- 
ufacture, and  Derivatives',  including  Artificial  Alizarin,  An- 
thrapurpurin,  with  their  applications  in  Dyeing  and  Printing. 

By  G.  Atjekbach.  Translated  and  edited  by  Wm.  Crookes,  F.  R.  S. 
8vo.  $5.00 

BECKETT. — Treatise  on  Clocks,  Watches  and  Bells. 

By  Sir  Edmund  Beckett,  Bart.  Illustrated.  12mo.  . $1.75 

BARLOW. — The  History  and  Principles  of  Weaving,  by  Hand 
and  by  Power. 

Several  Hundred  Illustrations.  8vo , $10.00 

BOURNE. — Recent  Improvements  in  the  Steam  Engine. 

By  John  Bourne,  C.  E.  Illustrated.  16ino.  . . . $1.50 

CLARK. — Fuel : Its  Combustion  and  Economy. 

By  D.  Kinnear  Clark,  C.  E.  144  Engravings.  12ino.  . $2.25 

CRISTIANI. — Perfumery  and  Kindred  Arts. 

By  R.  S.  Cristiani.  8vo.  $5.00 

COLLENS. — The  Eden  of  Labor,  or  the  Christian  Utopia. 

12mo.  Paper,  $1.00;  Cloth,  $i.25 

CUPPER. — The  Universal  Stair  Builder. 

Illustrated  by  29  plates.  4to. $5.00 

COOLEY. — A Complete  Practical  Treatise  on  Perfumery. 

By  A.  J.  Cooley.  12mo $1.50 

DAVIDSON. — A Practical  Manual  of  House  Painting,  Grain- 
ing, Marbling  and  Sign  Writing: 

With  9 Colored  Illustrations  of  Woods  and  Marbles,  and  many  Wood 
Engravings.  12mo. $3.00 

EDWARDS. — A Catechism  of  the  Marine  Steam  Engine. 

By  Emory  Edwards.  Illustrated.  12mo.  . . . $2.00 

HASERICK. — The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 
and  Linen  : 

Including  Bleaching  and  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  By  E.  C.  Haserick.  Illustrated  by  323  Dyed  Pat- 
terns of  the  Yarns  or  Fabrics.  8vo $25.00 

HENRY. — The  Early  and  Later  History  of  Petroleum. 

By  J.  T.  Henry.  Illustrated.  8vo. 


$4.50 


24 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


KELLOGG.— A New  Monetary  System. 

By  Ed.  Kellogg.  Fifth  Edition.  Edited  by  Mary  Kellogg 
Putnam.  12mo.  Paper,  $1.00;  Cloth,  ....  $1.50 

KEMLO. — Watch  Repairer’s  Hand-Book, 

Illustrated.  12mo.  $1.25 

MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks  by 
means  of  the  Prismoidal  Formula. 

By  Elwood  Morris,  C.  E.  8vo.  $1.50 

McCULLOCH. — Distillation,  Brewing  and  Malting. 

By  J.  C.  McCulloch.  12mo $1.00 

NEVILLE. — Hydraulic  Tables,  Co-Efficients,  and  Formulae 

for  Finding  the  Discharge  of  Water  from  Orifices,  Notches, 
Weirs,  Pipes,  and  Rivers^ 

Illustrated.  12mo.  . . $5.00 

NICOLLS. — The  Railway  Builder. 

A Hand-book  for  Estimating  the  Probable  Cost  of  American  Railway 
Construction  and  Equipment.  By  Wm.  A.  Nicolls,  C.  E.  Pocket- 
book  Form • \ • • • $2.00 

NORMANDY. — The  Commercial  Hand-book  of  Chemical 

Analysis. 

By  H.  M.  Noad,  Ph.  D.  12mo $5.00 

PROCTOR. — A Pocket-Book  of  Useful  Tables  and  Formulae 
for  Marine  Engineers. 

By  Frank  Proctor.  Pocket-book  Form.  . . $2.00 

ROSE. — The  Complete  Practical  Machinist: 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools,  etc., 
etc.  By  Joshua  Rose.  130  Illustrations.  12mo.  . . $2.50 

SLOAN. — Homestead  Architecture. 

By  Samuel  Sloan,  Architect.  200  Engravings.  8vo.  . $3.50 

SYME. — Outlines  of  an  Industrial  Science. 

By  David  Syme.  12mo $2.00 

WARE. — The  Coachmaker’s  Illustrated  Hand-Book. 

Fully  Illustrated.  8vo.  . . . . ...  $3.00 

WIGHTWICK.— Hints  to  Young  Architects. 

Numerous  Wood  Cuts.  12mo.  $2.00 

WILSON. — First  Principles  of  Political  Economy. 

12mo.  ...........  $1.50 

WILSON. — A Treatise  on  Steam  Boilers,  their  Strength,  Con- 
struction, and  Economical  Working. 

By  Robt.  WILSON.  Illustrated.  12mo $2.50 


> 


